A lot of the stuff in the hoards doesn't really sell for much. In my experience, people won't pass up hoards if Intuition is up, but they also won't go out of their way for them if not. The potsherds, on the other hand, offer you a choice of grade v materia, so you can pick whichever sells for the most on your server. You're also guaranteed at least two for a full 1-100 clear. So the idea is that rushing through means you can cash out sooner. It's not the most efficient thing ever, but it's not a horrible thing to do if you're gonna be leveling in potd anyway.
Just don't be a dick and refuse to leave the cairn if the rest of your party wants to full clear every floor.