That looks like a nice tool for squaring up a grinding wheel. I dress the sharpening wheels infrequently for shape, and frequently to expose fresh grit.
I have the small, coarse grit, silicon carbide stones that come with the Oregon grinders. I also bought a half inch by half inch by 6 inch stone at Fleet Farm for about six bucks, that I broke into 3 pieces, just to try.
These work fine for me, and will probably out last me.
Of course, I also use the conventional vitreous grinding wheels, instead of the CBN ones, so I might be a cantankerous old fart in training!
Philbert