They have demonstrated full self driving capabilities with a car driving “itself” to Taco Bell. I have a comma3 and have never had much success with that feature. The car drove itself very slowly and seems to just weirdly creep through stop signs. I think the last time I tested that was over a year and a half ago, so it may have improved.
I use mine only on the highways. I noticed for long trips (6+ hours), I can drive longer distances in one go and not feel as fatigued when I reach my destination. As an example, a 10 hour trip to visit family (11-12 hours including stops) I can do by myself in one day with the comma device instead of stopping halfway, or splitting driving time with someone else. For shorter trips (3-6 hours), I arrive to my destination with more energy than when I drive without these features. I am also able to focus more on potential obstacles further down the road than without it.
I think my device has already paid for itself thanks to a couple year period where I had to do that 12 hour trip I mentioned a couple times per month. Plus it is a really nice dash cam.