The issue with this is the one they tried to fix way back in LoTA. It was a long dungeon and nobody wanted to START it so continuously fished for Job in Progress, which meant for ages you would sit there with people leaving the queue. With such an application you then get most people not wanting to start any dungeon and everyone just sitting waiting for one already in progress so they can get rewarded for only doing half a run. This way nobody even bothers ever starting a dungeon unless they explicitly need it and anyone who wants to get anything done will have to wait for 3-7 other people who need it for progression instead of getting roulettes sorted in.