Buffing compounds are ordinarily made for use on cotton buffing wheels. As such, the finish they leave will be more dependant on the softness of the buff itself. So, a relatively 'coarse' grit won't cut nearly as deeply as if used for a stone or embedded in any other firm or hard substrate. I wouldn't worry too much about the rated grit, and instead look at the finish it leaves as you're specifically using it.
Compounds like these usually work very well on something like a denim strop (denim over a firm backing, like wood). They'll produce a polished, near-mirror finish on steels and other metals suited to the compound. A 'green' compound should ordinarily work on plain carbon steels (1095, CV) and low-alloy stainless (420HC, 440A, etc), at least. There may be other abrasive types blended into some 'green' stick compounds, like aluminum oxide. If so, they may also work on slightly more wear-resistant steels like 440C, 154CM, VG-10, etc. Those 'blended' compounds may account for the seemingly coarse grit rating too, as pure 'green' chromium oxide is ordinarily rated much finer, down to something like 0.5 - 2 microns in size. So, if it's actually coarser than that, I'd sort of assume something else is mixed in there too. That said, I'd still not worry too much about that, and see how it actually behaves in your application.
