Your skepticism is fine, but you are not really educated on Comma's product at all.

Comma uses a very strong adhesive for the mount, and then the Comma housing slides into that mount very securely. I don't think it is any more likely to fall off than your rear view mirror is (which also uses an adhesive).

Comma isn't a purely optical system, it also uses the car's forward radar information in addition to its cameras.

Comma does not pretend to be a fully self-driving system (yet), and in fact it has a camera facing the driver and will warn you if you are not paying attention or disengage if you are not paying attention long enough. It's a tool to make driving easier and safer.

I'm quite confident if you sat in my car while Comma was driving you would be shocked at how good it is.