They're just better
That was a roundabout way of saying you really like this European traffic management strategy...
Ok lame joke, let me circle back to my real point: having spent the summer in Europe and driving in multiple countries, they are better.
If you miss your turn, just keep circling. If you're scared how to do it, just creep along the outer rim. I bet they're even better for the environment because there's less petro- *ahem* gas used stopping and starting.
Lastly, they provide a great spot for victory arches, statues, and flowers.