It is not a waste and Hill is no longer a QB. He took very few snaps as a QB in camp. He really doesn't know the new system and could not run the full playbook as a QB. He likely only knows a few plays designed to get him a few easy throws on trick plays to keep teams honest when he is lined up in the Wildcat.
Haener and Rattler are your backup QBs. If you cut either, they are highly likely to get claimed before they get to the PS. And, both of them have upside from here. I think Rattler is better, but either one of them could end up being our future starter and the other a solid backup. There is no reason to cut either. It's taken years to find even one QB as promising as Haener and Rattler. Cutting one to try to put him on the PS would be a really bad move.