The only positive fact is that by staying longer, he can grab more details and data about several places, friends and enemies.
But it's only useful if he can somehow get over his mental stress.
One thing to note about his character: he's a shutin teenager. Of course it hurts and its difficult to deal with life and death situations in a violent environnement ruled by powers you don't understand, facing people who have survived this for all their lives...
It's like suddenly living in a country plunged in a civil war when you never ever encountered violence... Even at 40, I'm not sure I would like and tolerate the experience.
And since the reset only heals his body, I can understand why behaves that way.
Doesn't mean I wanted to watch that in my anime list...