For the 2nd factor, they should have some kind of non-electronic device which when inserted and turned, would allow the activation of the door and ignition of the car.
And if you lose your key? $$$ to get a new one. Want a copy for safekeeping or because you have additional drivers for the car? More $$$.
If someone wants to get into your car they will. They will just break a window. If they want the whole car they will get it. The only person who is having a more difficult time is the owner.