So, you couldn’t use these to mop a floor. The name probably derives from the mop-like look they get after prolonged use—sort of like the dark brown one at the top of the photo. The Yellow ones are just assembled and won’t look as moppy for a while. Sanding mops are lovely in the woodshop for sanding complex shapes because they’ll get into nooks and crannies. Depending upon the grit of the sandpaper, they can be more or less aggressive. I like to use these to get into the hollows of spoons and small bowls where hand sanding is awkward. The range of grits I use goes from an aggressive 80 grit to 120 and then a 220 grit shaped like a cup. You can use them in a drill, but a drill press is probably best.
I get mine from Canadian dealers ( Stockroom Supply and Lee Valley), but other suppliers sell them also ( unfortunately, I have no stock in either company).
If you haven’t tried this sanding tool and have an appropriate application, I’d suggest that you try them.