What this setting does, is that when an application requests the Microphone, then it automatically switches to HSP, and once the source is destroyed, it switches back to A2DP.
When I am using the headphones, and IF an application requests microphone, THEN I do want this switch to happen automatically. After the Microphone is not needed anymore, I want it to switch back to the HQ A2DP.
HSP makes the headphone quality much worse, and mono. Even while using the mic, that's not ideal. You might not notice if you're just having a conversation, but if you're sharing a video or watching/playing a game, you want the audio output quality.
I understand the quality issue, of course I also notice it.
But how else would my mic work? If it stays on A2DP, then there is no Mic input, so I used to have to manually switch it to HSP. With the solution I linked above, this is not manual.
So... I am not sure it does support it, TBH. I have a Bose QuietComfort 35 (II), and on linux I definitely have the low quality HSP+ mic (other thatn the quality, works well) and for listening only, A2DP is working too.
On Android though, calls are _MUCH_ higher quality with the mic on. (still somewhat different than from output-only, but less degradation than under my desktop linux)
