Removing an offensive buzzer or beeper or overbright LED is far more satisfying. Plus, nobody can trivially unmute the thing.

But that said, I wouldn’t mind a microwave that could be quieted without completely muting it. They could mute the buttons but still let it beep once when a timer or cooking cycle finishes. On the other hand I have a phone that I can time things with, so I’m not really looking to replace my microwave merely for that.