It's a very handy tool to have in your plug-in collection if you do a lot of recording. I have used it on artists I recorded who were 99% there but one or two notes were a fraction off and the program scanned the entire vocal track and fixed the imperfections. One time in particular was an opera singer and I couldn't use the "imperfections make the song better" theory because it really wouldn't have in this particular case. Not fixing it would have made the song worse and the singer had to take off so re-scheduling for two notes would have been a waste of time so I fixed it without even telling him and he just assumed he sang it perfect.
As Mykozo mentioned many artists use pitch correction... most likely, even your favorite band. It can also be applied to any single note instrument, not just singing... but I wouldn't recommend that, especially if there are a lot of single notes in a single measure (may confuse the plug-in and start sounding weird).
It's cool... I'll keep posting when I feel a piece of equipment is relevant or could help a fellow musician/studio engineer. I like to give back to the community when I can ;)

