With HomeAssistant, what is really use for Homebridge? Seems like it’s a stepping towards HA, and everyone upgrades eventually.

I haven't used homebridge, but have used HA in the past when I had lights and things hooked up. The UX and configuration surface always felt janky to me. So many little paper cut annoyances across every control / window / menu that you touch. The screenshots of homebridge seem much better at a cursory glance - if so, that's a net gain.

I use it to enable voice control (turn on the coffee machine), quick actions on iOS devices and for the simpler and faster Home ui for basic controls.

It’s also handy in that you get remote access with no extra port forwarding.

You get a no-nerdy interface to automate your smart home prebaked in every iPhone and tablet, and people don’t need to install anything.