There was only 1 time that this happened - it might have been after a [old] firmware update that increased power where after I gunned it and was regenning to slow down, my motor sounded like an airplane jet engine. I've never been able to reproduce it, but it was the only time where I felt like there was an audio representation of the power of the motor.
So if there had to be fake noise, I'd want it to emulate/amplify the possible/natural sounds of an electric motor.
I generally roll my eyes at the excessively loud cars on the streets these days, knowing that my silent tesla is likely faster. Loudness to me is a sign of inefficiency of power production.
It really depends. Exhaust / bolt-ons do add 10's of horsepower depending on what you do. But I agree it's a little funny to see muscle cars on the strip screaming while the Ninjas M3P or P100D take the win. But admit it, those exhaust notes still sound good.