>>40732553i dont want to have them tied to myth or folklore because that brings two problems
A) the concepts rapidly run out and invite a lot of bullshit (which is why Fate is shit since you can load up your favorite character with all of the bulllshit they did/reshape their myth to make them ultra broken)
B)it restricts the power system, so for example fubuki could very easily work with something tied to japanese folklore or she could work in terms of tributes/offerings, and million other stuff.
Basically, the more broader the scope, the more fun you can have with the setting, that way you avoid the basic but strong shit. Dunno if you ever watched Bungou Stray Dogs (Kinda fujoshit at times) but there, the powers are great but the author made the mistake of making a character whose power is ''powers dont work'' so all of the arcs start by taking that character out of the equation