I've done this in the past and that android phone was actually good only for safekeeping and I didn't installed any other apps for what it is intended for its use. But to lose some funds, it won't just happen automatically when you don't do anything stupid at all.

Yes, it's from the apps that we download and remember that we have to allow these apps for some privacy matters? that's how they can look at our photos and if someone is saving private keys through the photo galleries or notepad, they'll get what they want.

Highly unlikely but who knows if the internal systems and apps that are in there could be infected by malware.