analysis function?
you may only get a computer to analyze your games that has been completed.
you may only use database and analysis board on ongoing games.
you can use the analysis board to play out different candidate moves, how you believe the game is going, because it is not an engine and you may overlook a move.
Multi-day games are not played with the same rules as OTB chess. It's correspondence chess.
Correct me if i'm wrong, but you're talking about correspondence chess.
If that's the case then you allow to used databases, books, etc. That's one of it's benefits.
I think the OP might be talking about the Analysis Board, which is the equivalent of setting up a parallel board to your actual game and moving pieces around to look at the lines and possible positions. I use it all the time in my Online games, but I suspect it would be bad for one's OTB play, since you have to do all that in your own head. But if one views Online play as more akin to correspondence chess, it would be fine, since it's not using a chess engine to analyze the position (apart from the one that lives in your own head, of course).
I don't agree that it is bad for your OTB play. at the time I played otb and used the analysis board on chess.com I learned to calculate deeper since analysis board opened my eyes for more counterplay than I could visualize in my head at the time.
I used tactic trainer to train my skill to calculate without moving, I try to see the whole variation before moving in tt.
thus I had no problems using only my brain in otb games.
I like to use the analysis function to help my finite mind play out scenarios? Why is this an option? It definitely helps me play better than I normally would.