With heavy mixed traffic it's a nightmare for everyone. If pedestrians have the right of way (as they should) and there are a lot of them the whole thing would likely become a permanent traffic jam with almost always one car waiting to turn blocking most of the circle.
Partially true, given the huge congestion that there is, pedestrian have to wait for the green light even if cars aren't moving due to traffic. However, it is situated in quite an important node of traffic going in/out of the city. in smaller roundabouts we just have zebra crossing without lights, while in more dangerous and big ones (eg more lanes or often has heavy traffic) we have traffic lights
here in italy at certain roundabouts we have traffic lights that only work when a pedestrian called them. otherwise, the traffic lights flash a flashing yellow light and as a car you can use the roundabout as if the traffic lights didn't exist.
it's quite useful, if you ask me, it combines the best of both solutions. of course the traffic light has a countdown so if someone presses it immediately after having worked, it will wait for 30sec/1 min before being red again