I had known of stalemate (both causing and preventing it), but there are others as they mention there.
One other I think I have read about (I do not entirely remember) is that someone promoted to rook because promotion to queen would have taken more time due to not having a extra queen to promote to so they would have to go to another table to borrow it (or ask the tournament officials for it).
There is also nice discussion of the beautiful and practically relevant "Saavedra position", which does have an under promotion to a rook. https://timkr.home.xs4all.nl/chess/saavedra.htm
I had known of stalemate (both causing and preventing it), but there are others as they mention there.
One other I think I have read about (I do not entirely remember) is that someone promoted to rook because promotion to queen would have taken more time due to not having a extra queen to promote to so they would have to go to another table to borrow it (or ask the tournament officials for it).
Are upside down rooks not allowed to substitute as queens?
As far as I know, it doesn't count. But, I looked it up. Apparently, it is allowed in USCF but not FIDE.