>>34338330This is more of a general lore thing but
I'm aware of mega evolution's dangers and various adverse side effects, but has it been mentioned anywhere yet what z-moves might be doing to the bodies of trainers and their pokemon? There's no way something that concentrated and powerful is without risk.
The z-move pose the trainer does for U Necrozma's light that burns the sky really disturbed me. You can see the trainer nearly collapse in exhaustion after executing the move. So perhaps excessive use of z-power is actually a drain on your light/life force?