This is a great discussion and good for future reference as well. I'm learning more about sharpening all the time and currently into sharpening by hand on bench stones, but I'm definitely interested in eventually learning power sharpening as well. There's usually more than one right way to do things, and I can see some good applications for power sharpening.
I can see that the main applications for power sharpening are...
* Those who can't/won't do hand sharpening (don't like it, don't have time, health issues, etc.)
* Those who need to do a high volume of sharpening (for instance, they run a sharpening business, or a business where they use a lot of sharps that get dull quickly)