They mean that the audio quality you hear on the AirPods is better if you only listen to audio compared to listening and using the microphone. I don’t know if that happens on Macs too, but it’s certainly true when using AirPods on Linux because you have to switch the profile when you want to use the microphone and then the audio is really compressed for playback.

Yeah, it's the same on Mac/iphone but better codecs. Still lossy but better than the Android experience