While the website doesn't directly state it, the entire purpose of the Comma hardware is to run the OpenPilot self-driving software (or "driver assistance" software, whatever you want to call it). Sure, you can run other software with it, but it works really well with the software that has already been written for it and is available on the same website.

The FAQ clears some of this up (https://comma.ai/faq), but I agree with the idea that it is purposefully obtuse to keep regulators off their back.