I've used my Air for coding work. I found that I couldn't stick with it in Dumb Screen mode. I have astigmatism and the lenses to correct it; and my impression is that the lenses slightly contract the usable FoV which means you need the head tracking to be able to look around the screen more. That means you need the virtual desktop code running on the host (or the dongle, which I don't have) and the OSes you can use are them restricted.

With that, though, it's fine. The main reason I don't spend as much time in them these days is that I'm spending a lot more of my time in video calls than coding and we've not socially normalised big black sunglasses on video calls yet.