Not sure how to check that. However, I think there's a low risk on that front because, just from personal experience, I've been using steel wool for the past decade (manually cleaning) with no issue, and the brushes on the cleaner are softer than that; granted, they are spinning, so the cleaning motion is totally different. However, some commercial robot cleaners with spinning motions use steel brushes.
So, I think on that point, there's a good chance it may well be a non-issue for many, say for design engineering/prototype construction and for DIY enthusiasts. The tip cleaners certainly perform well for that, but to me, it's more irritating that there is a lack of spares.. which makes me think even more that maybe they are using robot cleaner machine parts to build these cleaners, and are just selling what they have.
I also don't like the cost*.. I think it's not worth it. If they were half the current prices, that would be almost a no-brainer, especially for users who didn't already have metal wool and a holder for it.
I'm currently using the Aixun automatic cleaner; I have not touched the JBC ball of metal wool since I've had the automatic cleaner. I do prefer to use the automatic cleaner. But still feels wrong to pay current prices for that benefit.
Those soldering at a sustained level frequently, or for production items, ought to continue to use brand tools; they wouldn't (or shouldn't!) risk affecting their processes to save a few hundred $). I think they are not really the audience for the tip cleaner models being discussed.
* EDIT: Plus, one may need to add on the cost of an AC-to-DC mains brick, depending on how confident they feel about the supplied one. I do not trust low-cost no-brand mains bricks, so I end up buying them locally from known trusted distributors.