I think Google wants to save their customer from the heat of their Android phone because if you were mining bitcoin with your Android, it will make your phone too hot and maybe it could explode because it's very hot to touch. Although I never try this, I think it's not profitable if you use android phone to mining bitcoin or the other coin because you will only get small hashrate to mining and you never get the profit. But if you only want to know the process, then it is fine, and you can try that app but you cannot do this again because Google bans the bitcoin mining apps.