I think in-line autocomplete is likely not that dangerous, if it's used in this manner responsibly, it's the large agentic tools that are problematic for your brain imo. But in-line autocompletes aren't going to raise billions of dollars and aren't flashy.

I'd say autocomplete introduces a certain level of fuzziness into the code we work with, though to a lower degree. I used autocomplete for over a year, and initially it did feel like a productivity boost, yet when I later stopped using them, it never felt like my productivity decreased. I stopped because something about losing explicit intent of my code feels uncomfortable to me.