Without the enter/exit rules, so any reasonable amount of traffic is going to cause many bottlenecks with merging and increased potential of accidents.
Migrating to this no stop merging scheme seems like it would be safer than changing all intersections from traffic lights to roundabouts where the majority of the population (e.g. America) has never seen a roundabout.
You may be right, having seen firsthand drivers almost launching themselves over a roundabout by not slowing down in both the USA & Canada.