To me, depending on the language, it's less useful than coc-nvim (too slow, breaks my tempo, too much added code, sometimes add stuff I did not ask for, or use old, inefficient patterns you only really find on shitty websites), so I still write the 'clever' part with vim, but when I write tests I now use VScode because copilot is really helpful (and it's funnier to use it than to write unit tests that work).

For languages I do not know well however I use it for everything. But I wonder if it keeps me from learning tbh.