I don't have a mute button. Actually, my laptop has one, but I'm usually on an external monitor with the laptop lid closed, so I couldn't get to it anyway.

There's always the speaker menu that I can pop up and select mute, but it's unnatural enough that my brain goes into panic mode when it needs to shut off the sound quickly. I'd probably just slap the power switch on my external amp.

So, this strikes me as a much, much more natural user interface than what I assume most people have on their existing system.