Some accents just doesn't sound very nice so I don't find it strange that many want to get rid of their accents. I have a Danish accent, which is possibly one of the ugliest accents when speaking English, so I am going to make an effort to get rid of it.
I also think that some of the regional accents in the UK might give a bad impression in certain jobs, speaking with something similar to received pronunciation will just sound more professional.
I am a trainer and while I have few problems in the U.K with my (West London) accent I do have problems with English speakers from Europe understanding me. This is the reason I want to change or at least reduce the effect of my accent and speech patterns.
My wife is Russian, she has a fantastic command of English usage, and a very good vocabulary to boot - however, her heavy accent means that often she incorrectly pronounces vowels and this makes the words difficult to understand when first heard by a native speaker. I think a book like this would help her, and others like her to improve their English. It's not about being 'snobbish' rather about communicating more easily.