[Shujin]

Honestly, I think the party leader aswell should have some sort of function like that. Espicially when they have emrcs aswell.
Cause whats worse than waiting for one turn to run out?...Waiting for 4-5 "Mobs" or more turns to run out because he is AFK, so he can't control his mercs either. Or summons.

Leaders sometimes puff aswell, and you can't really do anything if that happens, but be trapped in the endless waiting hell.

I wouldn't be worried about the grinding aspect...Mercs aren't that efficent that its worth it or outshines any other training method, besides, its risky and you can't start another battle while being AFK...So its really nothing to worry about.