It depends on what your use case is, I have both homebridge and homeassistant setup for different devices. But I also use HomeKit as the main hub of my home automation not home assistant.

For me both services are primarily for things that don't natively support HomeKit (my vacuum, logitech harmony, the receiver for my sound system, and a couple other things).

I also use home assistant to expose a couple of fake accessories for state tracking for some automation, and I do a little bit of more advanced automation in home assistant.

I use both though since some plugins in the home assistant side are way to complex (and causes issues due to that complexity) for what I need to just expose controls to homekit, or don't work as well as the homebridge version.

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.