If you have an Insteon hub, you can activate insteon scenes via HTTP from a RM rule in Hubitat. You can also create scenes via HTTP using Insteon linking mode.
I don't think you're ever going to see a native Insteon integration in the hub. However, there's a bridge application that was created some time ago, allowing you to use Hubitat with an Insteon hub. Although it's no longer actively developed, it still works fine and I have been using it for years. I prefer this over the HA integration since it's much more responsive. But the HA integration is good to have available for adding/removing, modifying device and hub settings, and creating Insteon scenes, without the need for a monthly subscripton.
You can create and trigger Insteon scenes from HA, or you can create the scenes on HA and trigger them via HTTP from HE Rule Machine.
Create and trigger insteon scene from HA (use HADB to trigger an HA automation via an HA toggle Helper, or use the HE>HA integration to trigger an HA automation via a Hubitat virtual switch).
Trigger an Insteon scene via HTTP from Hubitat (Insteon hub)
