Higuain and Dybala are in different situations. With Higuain you could probably question his weight and effort. And possibly attribute that to his struggles. Although for me, it's still a tenuous connection.
With Dybala, I don't think we can question his effort. So I don't know how benching him for 2 days will make him better. Will he try even harder?
The problem is he is not good enough technically to perform consistently. For example, every situation where his first touch should be with the right, he takes it with the left. So you could say maybe his success rate goes from 95% to only 10% with his left. Now some games he pulls it off time after time but eventually the poor fundamentals catch up to him and he will look bad.
He is not really made out to play as a CAM so he will go through stretches where his technique and decision making lets him down. I mean, has he ever been a player that passes when he should shoot? No. He always shoots. We knew that when we bought him. So he will inevitably go through a run of games every season where he will press the issue and sky balls from 30 yards when he should look to pass.
For example, he will receive a pass 35 yards from goal and there could be some combination with Higuain that he can play that is easier to complete. He could do that and no one would have a problem with him. But usually, and almost always, he will opt for a very, very difficult shot. Now at the beginning of the season it goes in the net and he is Messi. But it's an unsustainable play style. So these patches are inevitable. How does benching him fix it? I don't know. He hasn't changed the way he plays for almost 3 years now.