Actually, BYU is in Provo, Utah. The other college someone referenced is Utah Valley State College (UVSC), in the neighboring town of Orem.
Their program, while not quite as good as BYU's, is still stellar. In years that BYU does not go to Blackpool, UVSC does, and they clean up as regularly as BYU does. When they do go to the same competitions, BYU generally comes out on top, but UVSC is never far behind!
(Both have scholarships, but if you are female, and haven't been dancing since you were 10, I wouldn't count on a ballroom scholarship.)
Also, majoring in ballroom dance is no more useless than majoring in, say, English, History, or practically anything other than Engineering. Take it from someone else well-versed in higher-ed: most students don't work in anything related to their major, and most people change careers many times over the course of their lives.
So, you might as well study something you love. You'll be required to take other courses as well, and you'd do well to take some business courses.
I'd also recommend checking into placements for their graduates. What would your goal be in majoring in ballroom? Do you want to teach? Perform? Open your own studio? Whatever it is, is that a result that their graduates obtain?