I've been using OpenAI Codex directly (so not Github Copilot) for some coding tasks and it's been useful enough that I am using it daily at this point, though mostly as like a sort of personal Stack Overflow, especially when working with unfamiliar APIs. Prompting it with a function signature/docstring of what you want to achieve can give a helpful and often functional example that uses that API, even if the code is not perfect.
It's also decent at doing tasks that would be easy for a beginner programmer but perhaps tedious. Like you can give it a function for generating random colors and a task like "expand the variable names in this function to be better", and it will change variable names like `r`, `g` and `b` to `red`, `green` and `blue`. Hardly amazing, and the latency of the API means it's not actually that useful in practice (yet), but with the right prompt it can do some impressive things, and I expect it to get much better in the near future. Pulling magic strings out of functions into constants and adding typehints to Python functions are other simple tasks I've found it OK for.
