Very Exciting news! I had questions, so I'm watching the video for answers and sharing them here for those who prefer text to video.
The first thing I wonder is whether this means actual apple homekit certification, and according to the video - Yes, that's the plan. During the initial 'extended public beta' expect a warning from homekit that this isn't a certified integration, but they are working through the process to get apple certification for the full release.
Homekit support does not require a homekit hub device (AppleTV or Homepod), but it is recommended for a better experience. That's true for homekit in general, not a limitation of the hubitat integration.
I'm looking forward to finding out more about the capabilities and limitations, as well as seeing how it's implemented. One thing I'm particularly interested in that I haven't yet heard an answer to is whether this will be a 2 way integration. Will hubitat be able to see and interact with native homekit devices, as opposed to just making hubitat connected devices visible to homekit? For homekit only devices like my circle view doorbell and Schlage Encode Plus lock, that would be huge.