I was told not to use a rotating brush by Simonis. Doesn’t the roomba have one?
They have very short bristles. Yes, they rotate. I understand wanting to take good care of your cloth, the stuff is expensive. I would not recommend anything that would damage cloth to you. Simonis is covering their ass. Some harsh bristles like the old beater bar type could harm the cloth. These don't. They will not reduce the life of your cloth. If anything keeping the grime and old chalk out should make it last longer.
After about 4-5 times of doing it by hand you'll probably be sick of the process. These work. I'd rather run a couple racks of 9B and set the "roomba" to work instead of cutting the night short in order to clean.
I used to use a handheld Oreck and while it worked well, it is pretty annoying to spend several minutes doing so. I saw the robots in action at a local hall and at a buddy's place. It's really nice to have a clean table and not have to spend time cleaning. If your time is worth anything to you it doesn't take too many weeks of cleaning to get your money's worth. I think the one I bought was $95 at walmart.
I have Simonis 860 as does the pool hall and my buddy has 860HR.