One concern that I have is that copilot is inherently additive in nature. It is unable to suggest that blocks of code be deleted which creates a bias that adding more code is always the solution and a lot of code that shouldn't be written ends up in the codebase.
I believe this is a problem works against less experienced engineers because more senior engineers are better at recognizing that problem. In my experience the most senior engineers respond to that by just turning the tool off.