That's a sacrifice to create a triple fork. Queen takes bishop, knight takes c7 pawn, forking the king, queen and rook.
It's forced, since the queen is pinned initially. Also leaves the knight on that cosy b5 square when you're finished.
edit: Coming back to this one, I think you're right actually. Though white does have Qf5 in response, inviting the queen trade. This opens a few different lines, two of which do look good for white if black declines, kinda approaching a potential mate if black queen returns to d8, which seems strongest to me. I can't find the finish though. If black trades, white is still in a decent position, since the knight fork is open then, and the center file opens up a little.
1.) xb5, Nc7+ and get their rook (unless they decide to take their queen for your knight)
2.) xd4, get their queen (so yeah 1. will happen)
If they to for Nc6 you also can respond with Qc3 and win the knight (or the queen), unless they do Bb7, then you don't win anything but are in a very good position (very aggressive and they can't move anything away without losing material)
Unless I've missed something big you are correct; it wins the pawn which is nice, but it's hardly earth shattering as long as black doesn't have a brain fart and take the bishop. According to a quick look with Stockfish:
Bxb5 c6
Ba4 Qb7
c3 Nd7 and black has escaped serious consequences
... c6
Qc3 xB
Nc7+ Kd8
NxR Qb7
O-O Nc6 is bad for white, black has two pieces for a rook and change, and most of white's development has evaporated
... Nc6 is worse for black though
d4 Rb8
Ba4 Ba6
c3 Bb5
BxB RxB
O-O and the attack is over, but black had to scramble to defend and wound up down a pawn with a messed up position
You can try yourself; go to lichess and click the little live-analysis toggle on the left side up above the move list. Stockfish isn't perfect but it's better than any of us here.
probably because it's a sacrifice and if they take the bait it's a triple fork. even if they don't take the bait it leaves you in a better position. don't know about the brilliant algorithm of chess.com but it's probably a move above the player's level.