Tangent: please don't downvote someone asking questions, people. I for one had not considered that electric motors have no gears to shift, and wondered "surely both cars are automatic? Does Tesla have a patent on a faster automatic transmission or something?" so I appreciated someone asked.
The basic idea is that it is wasting time.
But this is no longer a factor as the gear change is instantaneous with Automatic GearBox.
Electric cars do not have a gearbox and just have one rotor.
This does place them in a disadvantage when starting though as there acceleration is affected.
Formula E cars, have started using a 3 gearbox for their cars in order to have a faster start.
So it is possible that the Roadster does have a gearbox.