All I'm saying is that it is human nature for form habits and when those habits rely on the unreliable bad things can happen. Maybe it's just the engineer in me, but when I have a choice between "might work" (stopping via unreliable regen on the accelerator pedal) and "does work" (stopping via optional regen on the brake pedal) I pick "does work" every time.
I understand your concern in general, but not in the context of what's being queried with this thread: having regen braking continue all the way down to 0 mph instead of the current 5 mph limit.
Currently, if I'm approaching a stop light, I lift my foot off of the accelerator in a fashion that tries to bring the car down to 5 mph right before I need to fully stop at which point I engage the mechanical brake. I'm not perfect so sometimes I undershoot, sometimes I overshoot. In either case I take corrective action (accelerate or mechanically brake) as needed. Regen won't suddenly become more limited in the middle of my braking sequence so I'll know when I begin braking whether regen is working leaving myself plenty of time to take corrective action. Moving it from 5 mph to 0 mph is simply moving the target.
Your concern seems to be more relevant to whether you should use regen braking at all since it can't relied upon to operate the same always. I still think it's fine because it's easy and intuitive enough to adapt on the fly, but for those that don't, they can simply reduce the regen and never rely on it.