1. This generally means it's easy to filter out candidates who aren't a fit for your organization. In my experience, most employers would love to have employees where the salary is not the first (or even top 3) factors in their decision to take a job. (Rare, I know.)
2a. That seems like a good tail into #1. The employees who aren't in it for the team/company/career filter themselves out. 2b. Or, it's used as a comparison for employees to better themselves. "I want Job xyz because I can make an additional $20k/year. How do I improve myself to get it?"