An insufficient argument.
Yours wasn't much of one either? "Oh it's shit but it's skippable shit." A dog's turd is still a dog's turd, and whether or not I step around it does not change the fact that it stinks.
You getbetter SP restoring gear but that's it. When you exit it comes back, but not inside.
So
if I had to say, leave, would all the dungeon specific relics and items I had gained be lost, or would they be returned to me upon my returning to the dungeon?