I think this is a case of some misguided product managers (and since German car companies are known to be huge bureacracies - no wonder). It seems like there is a great important safety aspect to it - that first you can hear that the vehicle is moving (there is an audio cue), and second is the affordance that you pressing on the accelerator has an effect (that the accelerator/electronics is not broken) - idem for braking.

Interestingly enough, railway engines had this problem solved a number of decades ago when they started using mechanical speedometers based on a clock. When the vehicle would start moving, the speedometer would start ticking. The faster you go the faster the ticking. Seems like electric cars need something similar (it does seem like a very useful safety feature to be honest).