Relying on crappy lane keeping and crappy self driving are equally dangerous. If poor software drives you off the road, why does it matter what the feature was named?
Anything before L4 is "driver assist", which means at the end of the day, the buck stops at the driver. Anything beyond L4, the car itself drives without requiring supervision, which makes a big difference. It's your responsibility to use lane assist in a reasonable way, it's not your responsibility to control how an L4 drives anymore. That's the point of self-driving, the "self" is responsible.
I don't disagree on the practical level, but I think that optically it is significantly different.