Google version is different than Github version (which has mining option).

You can download and mine with phone using latest v0.5.5-alpha : https://github.com/JSEcoin/platform/releases

(JSEmobile-0.5.5-github-android.apk)

You can mine with a rig too   If you have a rig that mines ETH you can mine JSE too, install JSE app (JSECoin-0.5.5x-github-Windows.exe 103 MB) and let it run in taskbar.

It will consume around 5 - 8 % CPU (on my OLD CPU). If you have newer CPU, most likely consumes less than 5 %.