What is the point in positions like this?

In this game, black was supposed to play 11. Qxg2. I played Qe6 instead. Looking at one database, it shows 7. Bc4 as the top move, along with some others.

So, that got me thinking. If my opponent didn't play 7. Bc4 and played b4 instead, what are the chances they would make use of the -5 "oversight" on both our parts? As you can see in this game, they didn't do anything better. My second blunder happened while I was talking to someone else, so I could have clearly played 16...Qxd3 in the hindsight.

Is there something more fundamental than just, "You could have had a pawn with 11. Qxg2"? Or is this some computer line that humans most likely won't enter? Either top GMs won't enter that position, or you will get patzers playing b4 instead and you can win like I did?

How important is this to know it is a "safe" poisoned pawn to take?

Qxg2 is not just a pawn. You are treatening the Rook at h1 and thereby ruining the White King position.

Ok