I can understand people just fine with the voice profiles provided by Bluetooth. Strictly speaking, I don't need anything better than that.

But it sure is nice to be able to make phone calls where people don't sound worse than they did with digitally-switched analog landline telephones in 1995. Bluetooth doesn't get there at all.

The losses of Bluetooth even compound generationally: The inescapable tin-can audio of Bluetooth at one end first gets transmogrified by at least one intermediate lossy codec for transmission across/betwixt the network(s), and then gets tin-canned harder when the far end of the connection is also using Bluetooth.

For perspective: 1995's phone calls were ultimately limited by the G.711 codec, which itself dates to 1972. I'm not setting the bar very high here at all.

Calls on AirPods don’t sound worse to me than on the phone speakers, I don’t think the AirPods noticeably decrease the quality compared to the stuff happening on the phone network.