Roundabouts: Are They For Improving Traffic Flow, Or Skids Practice?

Roundabouts are tools for aiding traffic congestion all around the world, more efficient than a four-way stop in ideal conditions. Or are they actually not intersections at all, but donut/drift/skid practice zones?

This Mexican V6 Mustang used one quite, empty roundabout to test the theory. What conclusions do you draw from this short test?

(Hat tip to SundayRace!)