I seriously doubt that clipping does any harm to the queen. Nor do I think it speeds supersedure. But if Rusty believes that, she also believes that young queens prevent swarming so I would assume a frequent supersedure would be a good thing, if that is true. Myself, I see no advantage unless I'm in the beeyard all the time and have a chance to see the swarm on the ground with the queen that can't fly, before they move back into the hive. They will still swarm, but with the first virgin out about a week later than their first failed attempt. If I'm there for that failed attempt it might benefit me, but the likelihood is low. Marking is very useful as it gives you more information. It also makes it easier to find the queen, but if that was all, it probably wouldn't be worth the effort. The real benefit is I can tell if it's a new queen or not, and if not, how old the queen is. All useful information.