Nitori made her that touch screen phone that’s popular in the outside world. But Hatate noticed everytime she touched the screen, there will be fingerprints. It made her feel dirty.
When Nitori asked, Hatate said she’s not comfortable using it without buttons, and that she doesn’t like the screen getting dirty with fingerprints. So, Hatate erased her fingerprints, burning her fingers.
Listening to that… well, Nitori just got freaked out