Earlier quoted context omitted.
They do sell a USB-C to headphone jack adapter. I got one, barely ever use it.
Of course they _sell_ a headphone jack adapter. That's the point of removing it. All the "weatherproofing" and "complexity" talk is just smoke.
I got quite some corrosion on the headphone jack of my Raspberry Pi 2B. Not sure why. But either way, these adapters can be bought anywhere, and they'll work on other devices as well. Like I said, I didn't use mine much. Usually Bluetooth with an adequate profile is good enough. I doubt people hear the difference between Bluetooth adequate profile and 3.5 mm in a double blind test.