This was originally set high because of performance concerns. We have
since improved things quite drastically. Even with a very low debounce
my song select is amazingly smooth.
This is about as low as we can got unless we want chaos when key
repeating left/right arrows (it's not as bad as you think, maybe worth
testing during review and see if it feels more expected?).
Of note, stable has key repeat disabled on left/right arrows and zero
debounce.
Addresses concerns in https://github.com/ppy/osu/discussions/24916.
While it is true that there is a transparency overlap, it is only seen when entering/exiting song select. And there are other components game-wide that exhibit the same issue when transparency changes. Should be reconsidered another time.