They are good for gaming and movies. Not too great to read text though. You can use them to work (read/write code), but it’s not a great experience imho. The resolution isn’t good enough to feel that I want to work with them.
Best steam deck experience I’ve ever had though. Sekiro and Elden Ring with a giant virtual display is fantastic
I find them awesome for reading text, but I generally plug them into my phone, It's usually displaying much larger fonts than you'd use on a computer.
As a rule of thumb, you probably want a font size similar to what you'd use on a 12 or 14 inch screen. People code quite well on 12 - 14 inch displays but it's not the advertised "57 inch screen equivalent" if you're displaying text.