You're right, it's not comparable. Jetbrain's code completion actually integrates with the IDE to guarantee the suggested code isn't entirely a hallucination -- for example it checks for unresolved references so that its suggestions don't reference non-existent variables/methods.

I've disabled Copilot as it produces garbage way too often. I found myself "pausing" to wait for the suggestion that I'd ultimately ignore because it was completely invalid. I've left Jetbrain's code completion on though because it's basically just a mildly "smarter" autocomplete that I'll occasionally use / I don't find myself relying on.