Basically, for the same reasons I originally switched to BlogEngine: cheap, lazy, old curmudgeon.
It's actually cheaper than BlogEngine, because I don't have to pay for a site on which to host it.
It's easier for me, because I don't have any configuration work to do if I want to add associated blogs, (of which I have several), which means my laziness is less of an impediment. I still haven't figured out out the telepathic blog interface that allows me to create a blog instantly from any random thought/drivel that pops into my mind when I wake up. So I still have to get up in the morning and go to my desk...
I'm still a curmudgeon, and even older than I was before.