Mercedes is taking legal liability for all actions of the car while it is in L3 autonomous mode, which Mercedes calls "Drive Pilot." That feels like more than a marketing gimmick, especially since no other automakers have assumed liability like this (that I know of). I am in stop-and-go traffic on the highway all the time during rush hour, it would still be beneficial to just read a book or work on my laptop while the car drives, even in that limited circumstance.