I think sometimes that can be necessary, just to get sufficient silence around the room to make it worth launching into the lyric, particularly if the first verse is important to the rest of the song’s narrative, but if it’s just to draw attention to instrumental skills which may not be that great anyway, I agree that is irritating especially when time is short for others waiting their turn. However, when I do that myself it usually means I’ve forgotten the first line, or am contemplating whether to switch the key down a little to avoid that high e in the chorus.