

As another commenter pointed out it does have a noticeable impact on mpg, however you can still do flush mounted handles that are fully manual. Basically every other car manufacturer does manual locks except for Tesla and a couple small (less than 10,000 units annually) companies. The thing is electric locks are cheaper, and when you don’t care about safety, you go for the cheapest option.

Electric door handles don’t need all the linkages, it’s literally a solenoid that’s attached directly to the latch and that solenoid is both the door latch and the door lock. There’s only 2 moving parts, the solenoid and the latch itself. The model 3, S, X and Y have an additional moving part that is the actual handle that triggers the solenoid, but the cybertruck doesn’t even have that.
My manual door handle has the outside handle, the lock, the inside handle, the electronic lock, the linkages between the lock and the outside handle, the linkages between the lock and the inside handle, the linkages between the lock and the latch, then the latch. There’s way more machining and assembly involved in a manual lock and door handle than an electronic lock, and that machining has to be way more precise.