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)
