I use it with the documentation of what I'm building.
Paste in the relevant section of the developer docs, ask it to write a function, or ask it to produce a valid API request, etc.
I suppose it's like a junior dev in a sense but it's very fast, can correct its own mistakes if you point them out, and has an internet worth of knowledge about various approaches and troubleshooting techniques.
I find most people who don't see value haven't actually used GPT-4 yet. Have you?
It's decent at coding and excellent at troubleshooting.
I've never seen it make a grammatical, syntactic or spelling error. With good context, it can write anything you want.
You need to have experimented with it a bit to know how to reliably prompt it, but once you get a feel for it the tool is invaluable.