Maybe it is due to the Spanish translation, but are Battle Sprites perks learned faster if we just give them their favourite food? Is it just due to us being old players that we feel that is just better to spam them with 4-5* materials as we have a lot of them? Because I don't quite understand the "maybe" part of learning Perks.
Does it actually matter what you feed your sprite with?
I just give then 4 star mats (as of now). Its random.