That electronium of whatever was called wasn't actually mining. It was fake type of mining. However technically you would earn actual rewards using your phone. Another 99% of all the other miners found on typically the Google App store are malware to steal your private info and private keys. They can even include clipboard attacks so if you try and send a bitcoin payment it will change the address to theirs.

Reason why there are no phone miners is obvious. They can't compete with GPUs and ASICs. If you took all the phones on the planet in existants the hashrate would maybe be equal to an ASIC or 2. Hence for a single phone there is no point.