What's the big deal about Business Analysts?

I've run into people that have done various tasks over their career that could be a bit of business analysis, and project management. They seem frustrated with the Project Managment assignments and would like to get into more BA work. What gives?

I personally think that most seasoned project managers have 80% of the skills needed for BA tasks. If they've ever completed a complex project charter, they've used most of the skills required for gathering requirements and specifications.

I know I end up doing project management on most of my assignments. Usually the Project Manager is too busy, or the project is too small to warrent a PM.