One of the common uses I've heard is for generating boiler plate code. I have two thoughts on this. First, you actually have to understand what the boiler plate code is doing for it to be of any value. Second, there are already solutions for this that work just as well or better. Most of the major IDE's either support code templates or have extensions for that. You just have to be willing to take the time to create templates. I use Resharper with Visual Studio for this all the time.
I tried copilot free for a month and was not that impressed.