depends on the knife and what its going to be used for. these cheap stamped blades i have right now take it well and i quench them as they grind. i can also re-temper if needed. i have some old hand made saw blade knives that i might start learning with. there is no need for me to go to the bench grinder on my higher end knives simple stoning does the job. on cheap knives where removing lots of material to get a proper bevel is needed grinders are quicker.

its really picking the best tool at your situation. grinder if you have to reprofile, stoning if you are just maintaining an edge.You would still have to do some major grinding and removal in a pass for it to heat up enough to take the temper out. i have found light pressure while slower makes a better tool. but most of my education on grinders was in a machine shop. making cutting tools for the lathe. slow is okay as long you do it right.

but hey im just learning still and not a master. and of course can be totally wrong.