Community building, yes.
And also, secondly, I would say, voting because you actually like something, instead of voting in hopes of getting voted back.
The latter is what leads to crappy content in the trending pages, and the trending pages is the first thing a person who visits steemit sees, and whether he stays or not often depends on this first impression.
Hopefully if money is spread around more evenly (which is what MSP is about, I suppose), the trending pages' quality will go up, and the community will grow as a result.
Yeah I had an odd impression from the trending when I first got on but the support posts and community they showed after setting up my account was what I was focused on so that helped.