the reviews online seem to be mixed. My main interest was for some bits that I have, in 0.1mm increments that I need to remain accurate- I wouldnt trust myself to do these on a bench grinder, not that I even have one.
However, I think that you are correct, that it is easier to just purchase them in the sizes that I blunt. uk drills seems reasonable for the money (my use is mainly in plastics and rubber), postage is quick enough, so it probably isnt even worth the investment in time to learn it freehand.