why did the game review engine say that a pawn should’ve been promoted to a rook instead of a queen?

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KingMe-KnightKnight
I did an analysis on my latest game and the game review engine says that my opponent made a mistake by promoting his pawn to a queen instead of a rook. Why did it do this?
KingMe-KnightKnight
Check out this #chess game: KingMe-KnightKnight vs tigerslayer78 - https://www.chess.com/live/game/137807705448
Gerian07

Maybe it would have been a draw if hè promoten to a Queen?

KingMe-KnightKnight
What do you mean? There’s nothing a rook can do that a queen can’t.
Fr3nchToastCrunch

It doesn't say a rook promotion is better when I look at it. There's no reason for an underpromotion at all, either.

Sometimes you have to give it a moment; I once played a rook sac that was considered a mistake at first, but then it was brilliant when I checked again.

Edit: I looked at the wrong move. It actually says they're both equal (+M11), which makes sense, seeing as that piece has to be taken either way, meaning it doesn't really matter.

Sobrukai

Sometimes underpormoting is necessary to avoid stalemate, or to to knight to prevent a weird checkmate.