That webcam might have a microphone. Your laptop has one too. Neither have a little LED to tell if they're on (the one on most cameras isn't hard wired to the sensor. You can sometimes turn it off in the drivers). There's a microphone in your phone, in your tablet, your PS4 controller, your land line (why do you still have one of those?!), that USB gaming headset you left plugged in, your fitbit, your overpriced voice activated IoT refrigerator (Your out of milk; here are some Amazon ads for milk), and your watch.
The potential to listen to audio on unpatched, compromised devices, is a huge attack vector! And yet we tape up cameras.
I suspect most people who currently tape over their camera would do the same for their microphone if it was as easy. But there's no easy, quick way to do it that allows to re-enable it when needed.
Of interesting note: ThinkPads have (had?) independent mute, volume and microphone buttons with LEDs to indicate volume or microphone muting. It's clearly at least partially software or driver driven, because with Windows 10 microphone muting is no longer functional.
The warm and fuzzy feeling that discovery gave me is why my daily driver is still on Win7 since I almost always have both audio directions muted.
The warm and fuzzy feeling should have gone away immediately upon discovering that it was not a hardware mute, but instead a software-defined feature... no?
I mean, if you can turn the LED off through software, it's really no better than the little menu bar icon that every other laptop has. If it were done all in hardware, that would be cool.
MSI laptops too. They have an Fn+Fkey, but when you use it, it disconnects the camera from the USB bus. It disappears from your device listings in lsusb/linux, or device manager on windows.
There's a difference between "I can turn this off as long as the driver is properly installed and has not been hacked" and "I can't turn this off." While the second statement is abstractly true for both, the bar for some software silently and invisibly turning on the microphone is quite a bit higher if it also requires replacing or hacking the audio hardware drivers.
The potential to listen to audio on unpatched, compromised devices, is a huge attack vector! And yet we tape up cameras.