If you take this example, you see a line indicating that cars should cede way to bikes.

In this particular example, bikes have right if way. There are also roundabouts where they don't, or where cars have right of way, but I think it's usually bikes.

Why? It's made specifically so that cyclists and pedestrians can be at an angle where it's easy to see them from a car. Motorists have a better view of cyclists and pedestrians than in a + intersection.

They are rare here in Montreal but we have a few like this on Nun's Island and they work fine without any traffic lights.

Not shown here. Usually the pedestrian and cyclists crossing is elevated. Along with the tiny island that narrows the access to the roundabout, they act as a speed reduction measures. Both intentional. It makes the drivers go slower, paying more attention and the traffic flow gets smoother. Coincidentally this makes this roundabout faster overall, as it prevents sudden brakes and full stops. Most drivers are in and out without noticing since they're too focused.

Edit: the cycle path is usually a level above the asphalt, like sidewalks, all the way through.