We all make mistakes when driving and don’t spot everything, and despite looking sometimes someone dives/flies into that blind spot as you are about to manoeuvre. So, it has a point in these scenarios.
As I a say, it’s to supplement your driving skills, not replace them.
You’re joking right? It’s meant to assist you AS WELL AS looking over the shoulder, NOT instead of.
Some cars don’t always light up for all vehicles (and also bulb can get broken, or system cease to work etc.) so always do the over shoulder check before changing lanes.
As for lane keep assist...