Associating bitcoin wallet with your mobile is a big no no no! It's not safe cause some hackers can hack it. Or for example you lost your phone with your sim in it, then someone found your phone, it is possible that all your btcs can be stolen from you by the person who found your mobile device, dude. Dont dream for it to happen.
If they ever do that they would make an deactivation like on a credit card, and as for hackers they will always exist as long there is technology. And as credit card cant be accessed without pin those smartphones could not be accessed without pin or fingerprint depends on what security it has.