I'm pretty sceptical about hi-viz TBH. When my wife and I used to commute along the A90 (mainly together in the morning, separately at night), we bought DHB jackets from Wiggle, mine in charcoal and hers in hi-viz yellow.
She complained of many more close passes and cut-ups than I experienced, so many that she sometimes considered using NCN1 instead. I found that I never had the slightest issue with close overtakes on that road.
What I would attribute this to I'm not sure. I'm a man and more scary? She looked more "pro" and didn't need to be given as much consideration? At 40-50mph there's not too much time for motorists to make nuanced decisions surely!
Yet, if she was hit, she'd be defended as having taken a sensible precaution, while in my case people would say I deserved it.
The same thing applies to i.e. flashing lights. I don't see that identifying yourself as a cyclist is useful around town, and prefer a big solid beam. We both have non-cyclist front lights and I'm certain far less head-on related issues than when I was running 2x 1W EBC blinkies.
Of course, sample size of 2 here!