AFAICT from the pictures, they work the same way as Pro-Filer and Bergman sharpeners - i.e., a slot centers the blade on an abrasive cylinder.
So maybe they can do more than remove burrs. I wouldn't be surprised if they can do everything - though, as with Pro-Filer, it is possible they are too slow (and would create too much wear on the cylinder) to change profiles in a reasonable amount of time - and even changing ROH would take a lot of time. To do those things in reasonable time, they would need a very coarse grit stone.
And of course a powered sharpener, that rotates, will be faster still. Like the Wissota tools, etc. For a professional skate tech who gets a lot of skate sharpening business, the powered tool would quickly pay for itself.
There was another company in the hand sharpener business at
http://www.thebladedoctor.com that made somewhat similar devices (but the handle was made out of flexible materials) that only fit hockey blades. But Edge Specialties sued them out of existence for patent violation.
The truth is, the idea behind such devices is very simple. But I assume machining them to high accuracy isn't something most home shops, even if they have metal working tools, could easily handle. Since abrasive cylinders are available for other purposes off-the-shelf, perhaps centering the slot on the cylinder is the hard part. Otherwise lots of people would do it
I'm not sure the Berghman device was a super-high-accuracy machining project. But it used spring pressures to make the device self centering, and to make it easy to adjust the gap size. Perhaps the Precision Blade device uses a dual pipe mounting bracket somewhat the same way? I thought of doing that, but wasn't sure it would work well enough.
As far as finish quality is concerned, a hand tool can do a very good job - if you lubricate it or use polishing fluid.