HLaB
Marie Attoinette Fan
You say that, but that's not how it works psychologically.
Unless you're properly drilled and trained such aids become a substitute for proper observation, not an aid to it. Its inevitable, invioble, how we're wried up to behave. Unless you've been drilled out of it and constantly practice the drills it won't make yo any safer - You just think you are.
Knowing accurately what is behind me well before a manoeuvre but keeping my eyes forward before the confirmatory look over the shoulder to a safe extent feels safer to me. Expecting vehicles or not rather than getting freaked out by them also feels better. It'll occasionally say something is there when its not, like a driver who turns off or when you cycle in parallel to another road, its never said it was clear when it wasn't but I'm not naive not to do that check. Its a bit like drivers and mirrors some naïve folk rely on them and forget to check the blind spot etc, but experienced folk always check. Until you've ridden with one its hard to form any conclusions; I've had mine for 5 years and I wouldn't ride without it these days.