That's not my experience at all. Copilot consistently creates implementations that are very specific to my app and manages to understand the context and problem surface spanning many files. It's not just getting a standard problem and pulls an answer from Stack Overflow.
Given Copilot's specialization for this task, I can imagine it being better at extrapolating from your own code. I haven't used it myself yet, so can't speak directly to its effectiveness, but I would imagine it would be good at automating much of the drudge work of coding, but similar to ChatGPT as far as coming up with novel solutions to problems. Which again, isn't to say it's not potentially a very useful tool!