The ssh daemon on the Caseta regular and pro bridges you are referring to is not officially documented by Lutron for 3rd party integrations (or supported for that matter). Not only that, but Lutron has changed ssh keys at least once in the past (it bit me when I used a regular Lutron Caseta bridge with Home Assistant).
It would be inane for Hubitat (or any other commercial vendor) to write an integration based on an unsupported API that could disappear on a whim. That would be a fun support nightmare, wouldn't it?
I should also mention that the ssh daemon does not give access to all devices paired to the Caseta bridge. For instance, Picos are not available .....
Finally, what makes you think that Hubitat doesn't support SSL?
Read my message immediately above yours. The ssh interface used by pylutron-caseta is not supported by Lutron. It has broken in the past, and can disappear on Lutron's whim.
There's zero chance that any commercial vendor will use that in a product for Lutron integration.
We actually had the connection with the SmartBridge working as you suggest about a year before we launched the hub, so in early 2017. But the absence of Pico functionality made it a non-starter. Picos are widely popular for Hubitat, because they can control any device in your system. A Lutron integration without them makes very little sense.
