It is not the cell phone it is the time travel part that needs the technical expertise. That is a non trivial activity...The cell phone just came along for the ride.
You missed my point completely.
Limps do not get cured at the present time, so why would anyone expect the ‘traveler’ with what is presently a common device, but in the near future probably will not be, to have had her limp cured?
Illogical.