There are a lot of downsides to losing a hand/arm, but one of the upsides is that your replacement arm can be tweaked with a lot more creativity than your original, fleshy version. Just take Trevor Prideaux, who now has a smartphone dock built into his forearm.
It's not just a gimmick, either. Smartphones are designed to be used with two hands, so Prideaux was struggling to use his by laying it on a flat surface or balancing it on his arm. But by putting it right in the arm, it's far easier for him to use with his one working hand.
It doesn't look like the arm charges the phone up, unfortunately. But I guess that leaves something for version 2.