It's better than traditional autocomplete, but not transformative. ChatGPT is particularly bad with JavaScript — you're better off writing that yourself.
It feels like how auto complete should actually work, but I haven't seen any exceptional performance from Copilot.
Like with Phind, the longer the code examples, the more errors.
But it feels a more fluid when typing boilerplate heavy code, which is nice.
Con: writing lots of boilerplate is less painful.
(So you get more boilerplate code)
The moment you work with something a bit more obscure, it just guesses.
Especially with TypeScript it's kinda funny, since IntelliSense which is right there, in the IDE, tells the truth, but is completely ignored by Copilot.