A better auto complete than comes with the IDE already is actually hard and most of the AI code completion approaches I've seen conflict with the built in auto complete and don't actually don't do better. I've tried a few things and usually end up disabling the auto complete features they offer because they are quite pointless for me. What happens is that I get a lot of suggestions for code I definitely don't want drowning out the completions I do want and messing up my editing flow. Aside from having to constantly read through code that is definitely a combination of not what I'm looking for and probably wrong. And it is actually extra work that I don't need in my life. A bit of an anti feature as far as I'm concerned.

But, I actually have been using chat gpt quite a bit. It works for me because it connects to the IDE (instead of interfering with it) and it allows me to easily prompt it to ask questions about my code. This is much more useful to me than an AI second guessing me on every keystroke.

Codex adds to this by being more like a team mate that I can delegate simple things to. It would be nice if it could notify me when it is done or when it needs my input. But otherwise it's nice.

I'm pretty sure the codex and chat gpt desktop UIs might merge soon. There's no good reason to have two modalities here other than that they are probably created by two different teams. Conway's law might be an issue here. But I like what OpenAI has done with their desktop client though and they seem to be on top of that.