You are either crazy or deluded. Mining on the smartphone is impossible! The smartphones cannot last 1 day when you are doing asimple thing like: calling, surfing on the internet, watching movies etc. So how it can sustain mining? The mining means that the cpu on the smartphone is doing very difficult mathematical operations to solve cryptographic codes. It requires a lot of energy, I think that after 30 minutes of mining on your phone battery will be dead.
You haven't read into this properly have you.
You don't mine from the phone, for exactly the reasons you listed. The app is simulated mining, not real mining. It won't tax the cpu. It's all about marketing and getting people to use the app/wallet/crypto in the mainstream.