Seems to me it should be safer to block the cycle lane to avoid having traffic pass on the right, so you really only have to monitor in front and to the side when making the turn. Cyclists behind will then simply either have to adjust their speed, or decide whether to cross into the car lane and overtake on the left.
This thread made me realize I don’t actually know the rules for this here in Sweden. I’ve inquired with traffic authorities, because unfortunately when searching on their site for cycle lane rules you only find a picture of what cycle lanes look like. :o(
Don't expect the throughput of an American city road. It's not unusual that only one or two cars can make the turn before the light is red again, if there are lots of bikes.
Here's a third option to consider: the cyclist does not notice your merging in to the lane or otherwise fails to react and smashes into the back of your car. At higher speeds this can be lethal.
Good thing this is done at low speeds. The car is basically going 0mph, because they are going to turn 90 degrees. And when I'm biking, I am BY FAR more cautious when approaching intersections. As you should be in a car, bike, motorcycle, or whatever.
If you don’t merge first, you have to not only consider cyclists in the lane but also whatever may be involved with the turn itself, such as people crossing the street you’re turning into, or other obstacles.
Basically you spread the risk over time and space instead of concentrating it all into this one maneuver at the end.
Perhaps because of better drivers and possibly better cyclists, the chaos that is rush hour cycling results in far fewer accidents than I would expect.