"The phone network"? As in the usually 8 kHz to 16 kHz quality call typically encoding at ~a quarter the rate of dial-up?

Of course that sounds like a tin can either way, it's coming in encoded with the quality of a tin can! People here are talking about modern VoIP calls (Teams/Slack/Discord/Zoom/etc) which have a snowball's chance in hell of sounding decent in the first place. HSP/HFP will often crank that right back down to traditional phone network quality again. You also lose stereo, which isn't so bad if the only thing you're doing is having a 1:1 call but kind of sucks for a background group call.