As Chuck stated the grinder is good for removing nicks in chisels but, that is where I stop. A bench grinder turns way to fast to use for sharpening. You need a low speed grinder for that and use the white wheel made for that purpose. I don't have a low speed grinder yet, but I will eventually buy one. For now after the grinder removes the nicks, I go to my trusted oil stone and have been teaching my students also. Like so many other aspects of woodworking, you can spend a fortune to get the latest technology, or, you can use tried and true old school that costs way less and gets the job done. How many pieces of furniture were built over centuries without water stones and diamond stones ?
Don't fear your tools, pay attention and respect the tools and avoid injury.