I mean. If your team is built around running the ball and you don’t really have the personnel to pass all the time skipping 7 on 7s doesn’t hurt except for learning to defend the pass
but take GIbson southern for example...they travel for 7 on 7s every year. Go down to the national select 7 on 7 and compete against top programs....Gibson southerns offense has been one of the top in the state year after year because of this. By the time the season starts, I would argue a lot of the routes and plays are already learned and only progress from there. The defense is also on board with coverages too.
Lots to benefit from but you can make a case against I suppose. But many who use them to their advantage can make the case on why they are great