If anything it sounds to me as if the comma provided a false sense of security. Drawing from experience driving 9 hours is already grueling. At hour 10, 11 or 12 would you have been able to take control during a failure of the system?
I recently rented a car and on a much shorter journey (90 minutes) I was struck by how much more tedious and frustrating it was to manually pilot the vehicle.
I think the thing that makes driving grueling is that you can mostly drive at a subconscious level. Staying in the lane and matching speed are mostly automatic, but occasionally you zone out for a second, or get absorbed into the audiobook. Then you start to drift to the edge of the lane or get a little to close to a decelerating car in front. Then there is a hard attention snap where you are forced back to focused attention of the driving task.
An L2 system does marvels for just smoothing out those peaks. It’s much less frequent that you have to intervene, so your attention can stay at a much more comfortable level and smoothly ramp back to high focus when a situation presents itself.
If the system does something you don't like you just grab the wheel or touch the gas/brakes (the control messages it sends are lower priority for the car than driver inputs). It's also designed to disable itself if it sees gas or brake input.
It's really best considered as an upgrade to the stock lane keeping assist and dynamic cruise control found on most cars. Compared to the stock systems it's much better behaved (my stock Toyota system will happily drive straight across multiple lane lines in certain lighting conditions and it astounds me that such a thing could be sold), but it is a long long way from Level 4.
The same people who cram an orange in to their Tesla's steering wheel will just download a sketchy repack of the open source software that disables the attention checks.
I remember Hotz making a big deal about tracking the driver as much as the road. Which is something Tesla is behind on.
If you have no option, you just get it done.