In my opinion only (and I am by no means an expert):
Usually it's quicker, and if you are looking to go into grad programs such as Business or Law school where the major doesn't count, you can get a higher GPA and qualify for those options easier. Also, for some people (like me!) the subject matter(s) is/are easier. I love History, English, Psych, Poli Sci, and while I currently work with Business/IT, it's not as much fun for me to study for MicroEcon as it is American Lit
Military- you mentioned Officer, also to get quick points for E-3 vs. E-2, etc.
Grad School- Law school, medical School, some Business schools/majors do not care about your undergrad major
Government jobs- people just want to get *a* degree to qualify for the job, especially for a government job.
All of the above, except for the military reasons, are why I am doing it. Also, flexibility. Agreed, General Business is flexible, but what if down the road I wanted to do something in non-profit or work for a university, or decide I want to teach adult ed classes? Liberal Arts/Studies is more flexible than Business. Downside to it is it usually requires further study/training down the road (i.e. teaching cert, business core classes, computer classes, etc.), whereas a specific major you have your training.
I work in Marketing with IT (I do web support for a Big 3 auto company)- we require you have a Marketing or Advertising degree to do it. If you have a General Business degree, you need to get a certificate in Marketing. If you had a degree in Marketing, you can do this job and many others, but what if next year you want to do Finance? You'll have to go get additional training-sometimes a specific major can be a hindrance.
Then again, the way the economy is, having a degree is always better than not having one, period. Doesn't necessarily matter what it's in.