Can't speak for intelligent autocomplete writ large, but I treat it as an ergonomic feature, and Cursor's implementation is pretty good (though I'm not sure it's improved all that much in the past year).

It constantly takes whatever is currently visible in your editor to feed its context. If you get a nonsense/hallucinated suggestion, you can accept it, get it to read the error message from LSP diagnostics, undo, and then it'll correct itself next time. Or if you need to make changes in 5 places, and the next 4 changes are easy to guess after seeing the first one, it'll guess the next 4 for you.

I still use standard IDE features extensively. The intelligent autocomplete is just another tool to reduce typing when the next change is easy to guess.

Oh, and I turn it off when I'm writing prose or need to actually think deeply. Then it really does hurt more then help.

(Worth noting: I currently work primarily in Go, which is a language that's ridiculously verbose and has lots of repetitive patterns. YMMV for more expressive languages.)