Because even institutional traders have their own consumer lives. They have the same issues with their smart phones that us peons have...
Reasons this is a selling point:
1. People own many devices and don't always remember to charge the one they'll need most, or need next
2. People lose charge cables/adaptors, or share them between several devices. Their kids steal them as well. They also break or wear out from daily usage.
3. Sometimes the electricity goes out. Our power grid is less reliable (though POET may help in that department as its tech makes its way to the power-hungry server farms) than ever and it sometimes stays down for days in places where extreme weather events strike
4. Not everyone drives; car ownership is declining, so charging a device while driving is a tiny bit of a luxury for some
