CBN is intended for 'hardened' metal, which is kind of ambiguous. It is fine for A2, which is what most modern bench chisels and plane irons are made from. Softer carbon steel, like lawn mower blades will clog them up. I think the main advantage to the slow speed grinders is that, especially if you are learning to sharpen, you will lose less metal each time you sharpen. When you are experienced, you learn and know the difference between sharpening and grinding. If your CBN wheel is loading up, some places have very hard aluminum oxide sticks for cleaning the wheels. It does work, but puts a LOT of dust in the air. For a turner, just sharpen your scrapers several times and that will peel the loading particles off of the wheel. More so if the tools are V10 or M42HSS.
robo hippy