How is this a Mistake?

I like to learn from my mistakes I made this move trading my bishop for a knight which I understand that they say don't trade you bishops for a knight but like there worth the same and also this was my bad bishop since I had pawns on dark squares, now I know the position could open up and it could become a strong bishop but like I don't know even know what I am talking about, it doesn't even give a clear reason why its bad like someone make this make since like why was this so so terrible that they say it is a mistake. Now be3 has +1.51 and to that I say like what I don't understand like someone just make this mistake make since to a noob like me.

Sorry here is the entire image it got cut off because it was to big, obviously. hmm c3 honestly didn't think of that.

Hung your bishop

I didn't hang my bishop, I traded it for a knight and it's saying it's a mistake with no clear reasoning on why.

Bxf6? cedes the bishop's pair.
Be3 preserves the bishop's pair.

It is again amazing how useless and bad Game review is.

"This is an unfortunate error" just sounds like some placeholder nonsense comment used in development, replaced by a real comment before the product is launched.

Would it be hard to program it so that "the Coach" says "Trading a bishop for a knight is not good in this position" or something like that?