Most roll hoops are only cosmetic, mostly they only bolt onto flimsy sheet metal with no bracing and are only made from flimsy thin wall tubing.
So if you are after protection............don't bother, proper roll over protection isn't going to be a quick bolt on fix.
Unfortunately the layout and compact nature of our cars doesn't lend themselves to a quick easy fix, there is little space to put proper load spreading mounting points and accommodate brace bars.
In fact most of these things are probably more dangerous fitted than doing without, in a rollover they are likely to significantly deform on impact....with the distinct possibility of making contact with the occupants heads when they do.
Worthwhile protection needs to be engineered and integrated into the structure of the car.
Compromises to cockpit space, access and convenience, that such a proper rollbar would require don't much matter on a race car, but won't be much fun in your daily driver or weekender.
I've had the dubious pleasure of race cars on the road, whilst it's a bit of fun, you wouldn't want to live with the compromises, and the first one that comes to my mind is the rollbars.
Now I'm not saying don't fit one for cosmetic purposes, if you love the look by all means fit one, but don't try and kid yourself or anyone else that it's a safety feature,
"Keep calm, relax, focus on the problem & PULL THE BLOODY TRIGGER"