A new concept that using your phone to access your assets.
But there are some problem:
1. When your phone has been stolen
2. When your phone has been slowed down but you can't re-install or install a new rom.
There is a recovery feature in place where you can generate recovery shares, for example you can create 5 shares and distribute them to friends, family, bank deposit box etc. and then only need 3 of those 5 for a successful recovery. The same applies to your second point, in that case you could switch your phone and then just import your backup phrase again.