There's nothing wrong with using electric motors to turn a car's wheels. As a matter of fact, there's a lot right with it, starting with the fact that electric motors produce peak torque from the jump-off, which can make for great big smoky burnouts.
The downside is that it's hard to carry volts around in a lightweight, portable, easily-refilled form. Given current and near-future battery technology, pure electrics are going to be confined to urban runabout duty for quite a while yet.
Slapping an electricity-generating motor on board is the current fix for this shortcoming and most applications use fairly conventional piston engines in this role, although Jaguar has been dabbling with micro turbines for the chore. Meanwhile, some Jerries have let their gadget freak flag fly and come up with this solution. If you're not using the pistons to turn the wheels, there's no real need to have them physically connected to anything, is there?