If I were on the receiving end of this sacrifice in rapid (1600) or blitz (1300), I would take the time to analyze possible game continuations, as since white just sacrificed a full piece, black will have an easy game if he manages to survive white's initial onslaught. Assuming white's idea is to justify the sac with Qa6, I would accept the sacrifice try to exchange the queens with the move Qb5 (possible continuations for white include Bxa7+, where white loses his initiative for a rook pawn, and Qxa7+ Kc8 Qa8+ Qb8, where black appears to survive).
On the other hand, if I was black in this position in bullet (where I'm rated 950), I might eventually blunder under the pressure, as white has easy attacking plans, such as lifting their rook to d3, while black needs to find a way to activate their kingside whilst continually paying attention to white's queenside threats and their clock.
While the sac ultimately appears unsound and could be considered a mistake, the surprise value and threats generated by Nc6+ could cause black some serious problems if he's not paying attention, especially in blitz or bullet, where sacrifices need less justification. In any case, whether black survives the sacrifice or not, one can always review these critical moments after their games to analyze the missed opportunities and strategic plans for both sides to further improve the quality of their play.
Here is a piece sacrifice that objectively may not be sound but practically specially in low time controls may not be easy to defend. What do you think and how would you do against players at your level in different time controls?
In my personal experience they are crushing in blitz and bullet, not always by attack but sometimes by time also.