That was the first rule of the motorcycle training course: you're harder to see. Worse, I've had people seem to make eye-contact with me and pull out, and then saw the shock on their face when they actually noticed me; someone once described it as a bad check, where they're looking for cars, and since you're not a car the road's clear. (It's such a confusingly bad heuristic, too, since people seem to do that to trains and trucks as well.)

So to help things along, it's useful to be conspicuous. In overcast, low-contrast weather, I'd love for this stuff for my chaps when it's cold and drizzly.

EDIT: I wonder what the high viz stuff triggers in terms of object collision warnings in the head. Like, perhaps it seems like a sign, and that makes a person double check they're still on the road? I have that sort of knee-jerk check when someone with bright blue headlamps get behind me, since that color in a mirror used to invariably mean police.