If you're starting from scratch, going to college for the first time, with no work experience or background, you're right. Much more sensible to earn a useful degree, than an aviation degree. An aviation degree is roughly akin to certification in underwater basket weaving.

If one is already working, however, and has experience and certification that can be used toward a degree (eg, an ATP, A&P, etc), it makes sense...especially for some of the online degree programs. This is definitely true if one is entrenched in one's career, and is looking for the degree as a qualificaiton, rather than a career field certification. Get the credit for the flying, then hammer out the degree with as little trouble as possible.

In that view, programs that offer professional aviation degrees based on present certification and experience make a lot more sense.