They're not a joke, they have valid uses. Brush Research Manufacturing makes them. They're called flex hones or brush hones or ball hones.
When you're reringing an engine they work without having to use a torque plate, they follow the cylinder better than a rigid hone like the Sunnen pictured above. You may find them in many places. BRM makes many different kinds of ball hones for many different applications.

When boring and honing a cylinder sometimes the flex hone is the last step after the rigid hone, because it creates a surface with more flat area. It also cleans up the tiny folded bits of metal and sharp points. Look at the photomicrographs on the BRM website to see what I'm talking about.

They do not work well to produce a true cylindrical surface like the rigid hone. But if your cylinder is cylindrical enough in operation (warm with the head bolted on) they can get you a surface for the rings to seat on if you're concerned about them not seating otherwise...

R.