I see, no need to buy basic elements and ninja skillsThink of it like you winning is like a bounty. Say any console game, you beat something you can loot and xp. In this case, the kumi is your loot, the xp is for your rank up.
Yeah it's a grind based system, not permission based.
Look at the top of your screen, under the banner, it says "Shop" click on that, and go on "official kumi shop"
And no more battle test, yeah it's all about the grind now!