A very junior developer that brings me code snippets that are sometimes plain wrong is not useful to me directly - such a developer costs more time in review than they save by providing the snippets in the first place. The value of such a developer is that over time and with some mentorship they will become a slightly less junior developer who can bring me whole features that I can be reasonably confident are mostly correct.

Having said that, I don't know how the much more integrated write/review/edit cycle will work in practice when using copilot. I don't think it will be the same as a junior developer/pair programming partner in any real sense. My initial reaction to copilot is negative, but I'm open to being proven wrong about it.