Unlike with costumes, sprites do not have a selected sound. You can however, create a variable for the purpose of keeping the name of the selected sound.
Months ago, I made a report to add the latter behavior to () of sound (). You could do that with costumes in () of costume () by leaving the first input blank, but not for sounds.
Oh dreck. I agree. I cannot tell how much it drives me crazy when I see blocks are slapped into Sensing, out of any other categories that fit the block more.
(where is the (() @>) block used?::sensing) (in SciSnap!) should be in Control.
<[abc 123] has [letter V]?::sensing> (in a different Scratch mod) is among the worst offenders. This goes in Operators.
It is in Sensing probably because the block used for finding the sprite’s sounds (my ()) is in Sensing too.