British Columbia

yes they are - you just make shit up

They are demonstrably safer by avoiding t-bone collisions

Yes, there is a learning curve

The same can be said about literally anything. No car infrastructure is safe when cars just barrel into them without looking - only infrastructure made to prevent cars from passing, which is not the point here.

the are not safer when cars just barrel into them without looking

Is that something that happens? We have a mix of roundabouts and regular intersections in Vancouver, as well as some very questionable drivers. I can't think of a time when someone messed up at a roundabout. Especially the smaller residential ones