L3 is profoundly unwise. L3 can disengage at any moment. The attention required of the human in order to drive safely exceeds that required in L2, and is much more difficult to maintain.
A L3 car is required to be able to handle all short term situations and only do a handoff with 5-10 seconds of warning. The idea is it’s ok for the car to come to a complete stop and say I have no idea what to do, but it isn’t ok to simply fail on a freeway at 70 MPH.
Failing safely is a huge difference, as mentioned in the article: if a driver doesn't take over when prompted the car activates the hazard lights and slowly comes to a stop before making an emergency system call to alert first responders to a potential problem.
But it's absolutely true that the practical difference between "human must supervise" and "human must be ready to take over" is MUCH smaller than people want it to be. Mostly everyone wants to yell about Elon Musk and "2 vs. 3" is ammunition.