IMHO this is the way to go. Students like these tend to have freedom to choose whatever advisor they want. For example, in Cambridge self-funded students typically do rotations to see how labs look like.

This minimizes the possibility of ending up with a bully or someone incompetent. And if you do, it's much easier to run away to a different group.

The funding makes a huge difference. A student that the advisor doesn't have to fund that has initiative and workable ideas will only require occasional face time. To top it off, the ones I've seen that were like this were usually more senior, coming from some experience usually in the industry, and as a result more savvy; therefore they knew what leverage they had and were able to walk away from bad situations. But an RA that gets paid out of grant money will have a lot less leverage.