I've only been on since January and have only added people I actually know (except for MStreck), which totally defeats the purpose so I'm gonna have to change that up.
You could think of it as a type of Lynced-In service and use it that way if you wanted....
I don't think Facebook itself will help create opportunites but integrating it with other services and apps as well as linking it into your community and lifestyle (outside of music) creates an interrelated snowball effect and THAT could help lead to opportunities.
Facebook actually has a term for this concept and an illustration of it buried deep somewhere in their help/terms links.... can't remember what they call it. Anyone?