Because most mics are still using Bluetooth 5.0 I use the microphone on my Mac even when I'm wearing a headset. Otherwise, it puts me into a weird codec mode of ancient history where I get downgraded to a low bit rate and even my audio input to my ears sounds horrible then. So I always use the Mac microphone when possible.
It's more annoying on Linux where you have to manually switch... at least most apps in windows/mac will automagically put my headset in the correct mode.