Earlier quoted context omitted.
I love the fact that I can keep them in my ear and just go on my Macbook and select the output from the volume icon. I’m always amazed by that.
You know the truly damning thing is that we’re all surprised by this feature working. This is exactly the sort of thing that should be completely painless.
One day I wondered what happens if it can see two paired devices - does it forget one? Is there some unusably awful UX? Does it brick them altogether?
So I paired the Linux laptop. The dongle (which says "Connected" when I turn it on normally near the phone) now says "Second. Device. Connected" when it can also see the laptop. It appeared as one of the output options in the laptop's audio settings. If you play music on the phone, or receive a call, the music on the laptop stops, and you can take the call (or listen to music) instead.
Essentially, with the cheapest available product it appears to be as you say "completely painless". What exactly are Airpods / Apple doing here that makes it worth the extra? Maybe the voice telling you what's going on is nicer?