Unless the mobile version changed from when I last played it (and maybe it did. It's been like, a year), they seem to have streamlined a few things and got rid of some of the particularly stupid cash shop mechanics. Like that utterly infuriating one where you couldn't de-equip an item from a character without an equipment oil.

Funny thing is, the equipment oil is still mentioned in the tutorial for this game. It just no longer is needed and no longer exists as far as I know (thank goodness)