By saying "check", you have killed the cat.
Magnus Carlsen new chess variation: he trolled his team in this video
That's something I didn't think of, that with my rational the king could move to e2, but then it could be captured. Definitely seems this way of thinking is less consistent with the regular rules than what you were suggesting. So yeah, seems to make no difference unless you add a lot of new rules with it.
A chess variant where pieces change on various moves would definitely take some getting used to.

"Also...sorry if offended you by not following the #1 unwritten rule of forums in that every single post must contribute to the collective knowledge of earlier posters."
Well, you really should follow rules like this. Or at least not break it so blatantly. Is it against the law or some horrible thing, no, but it's still pretty objectionable in my book. Follow the damn unwritten rule. It's easy to do, it just requires some courtesy.

"so if the pieces are changing every half turn, then effectually, they are not changing at all."
It's probably technically correct, but kind of a crappy way of putting it. I don't see what it contributes. You could have just said, they change, but it doesn't matter. Sounds less fancy but less pedantic.
"Really, this discussion is pointless, so is it even, effectually, a discussion?"
See how annoying that is? Yes it's a discussion, lol. It was a thread someone posted, and people are making posts on it. I don't care if one can change the definition of discussion to make it not a discussion anymore.

to be in check would mean that your king is at risk of being captured the next move, but if the next move they change back to a knight, then you were never at risk to begin with....so you literally could not pin a piece with a bishop that is changing back into a knight when it is your turn.
Yes, this has been mentioned by me plenty of times. I have challenged what counts as "check" in the comments on this forum. Again, you have not said much of anything that has not been said, here. Yeah yeah, it doesn't put you in jail, but I would think, someone genuinely interested in discussing would want to read a few pages of comments rather than repeat stuff already said as if it was the first time.

I hope this example of extreme's helps clarify what im trying to say that pins during your opponents turn are meaningless....
Or... one could just read comments already made in this thread.

The more interesting part of the discussion was beyond that early point, where we postulated that the pieces change every full move. That, as well as the idea that your moves change your pieces. That would effectually change pieces, since if white plays Nf3 and black plays Nf6, white's Nf3 is now a bishop, since it changed before black's move, and black's move did not change white's bishop back into a knight. But of course, let's spend no time on that and spend pages answering a question that was already answered way early on.

The image below from post #23 explains everything.
Magnus was right. After his last move, the black king was checkmated, according to the rules of his new chess variation.

"Also...sorry if offended you by not following the #1 unwritten rule of forums in that every single post must contribute to the collective knowledge of earlier posters."
Well, you really should follow rules like this. Or at least not break it so blatantly. Is it against the law or some horrible thing, no, but it's still pretty objectionable in my book. Follow the damn unwritten rule. It's easy to do, it just requires some courtesy.
Thank God i have you here to hold my hand through the forum weeds. God forbid, one of us pedantic fellows just so happens to not read earlier comments.
Lighten up man

"Also...sorry if offended you by not following the #1 unwritten rule of forums in that every single post must contribute to the collective knowledge of earlier posters."
Well, you really should follow rules like this. Or at least not break it so blatantly. Is it against the law or some horrible thing, no, but it's still pretty objectionable in my book. Follow the damn unwritten rule. It's easy to do, it just requires some courtesy.
Thank God i have you here to hold my hand through the forum weeds. God forbid, one of us pedantic fellows just so happens to not read earlier comments.
Lighten up man
Which breaks another unwritten rule of life: when someone messes up, don't blame the person who didn't mess up, lol.
This is especially the kind of thread in which it would make sense to read the comments to it, because this is basically a puzzle (as opposed to some kind of political discussion). The community gets closer and closer to solving it with each post. So to go backwards to an early step (and act like it's something new) makes zero sense in this context and is a little annoying.
I could see if it was like 20+ pages, but (at the time) 3 or 4? I mean... especially if you clearly read the first two pages, why not see the whole thing?
But in any case. You've heard my side of it. I wanted to make sure of that :)

just to clarify:
1: the knights and bishops only alternate the turn after it is moved- as demonstrated in the above diagrams, so the black horse on b8 is still a horse and thus cannot capture whites piece on c7.
2: whites piece just captured the pawn on c7 as a bishop and is preventing the black king from moving into check on d8- it is considered moving into check even though whites piece on c7 would no longer be able to capture the king if theoretically it were to move to d8 because at the start of whites next turn his piece on c7 will turn back into a knight.
3:while the king is not in check directly like we have in standard chess, due to the funny way this variation works the black king will certainly be captured by the whites knight on c7 next turn and therefore it is (check-)mate.
because the power of a piece comes from what it can do when it is its owners move
Well, in normal chess this consideration never comes up. I've always treated it as the power of the piece comes from the squares it's influencing currently.
But like I said in #81, yeah, if you use that rational then it's back to the rule makes no difference.
A different way of seeing it is both kings are in check at the same time, so white has to move his king before he tries to capture black's.
So in your example, after Nxd4 "check"...white has to move, but he cant move to e2 because when the "Bishop" returns to being a knight, it can take on e2. But this would mean that the piece, whatever status it is in is influencing both squares e2 and f2....which is to say it is both a bishop and a knight...at the same time! Quantum Chess!!