I agree with, though perhaps my narcissipower is greater than hers, because I can definitely see less "altruistic uses" of the site.
As someone who is currently "lazily seeding" his blog with old Quora answers, I totally understand where this question is coming from… In a lot of ways, the directed nature of Quora helps with writer's block, and by staying within a few key topics, one could even create some thematic consistency to help with blog audience acquisition/retention, SEO and that sort of thing (I totally fail at that bit, btw – weaving together answers about sex, food, comic books, and the Internet… Okay, maybe those are a lot more related than I give them credit for, but still).
I've even seen some of the Quora regulars' own blogs occasionally acknowledge that a given post was inspired by a question/answer on Quora, or even a debate in the comments.
So, overall I'm just saying that Quora makes for a great place to work on one's writing style and tone, to tighten up language used, or let it fly loosey-goosey, to experiment with extremely technical answers, or bitingly sarcastic ones. If done right, all these little experiments wind up also being good answers to varying degrees – serving both the Quora community's needs, as well as one's own.
Still, I'd say that the odds of Quora becoming a blogging platform by default is a lot like the odds of a Wiki site, or even a community forum doing the same…
To me, it's more of a square-rectangle issue… Quora definitely has a format and process that can inspire (or kickstart) blogging within the site or externally. Trying to come in as a blogger, and declare Quora your chosen platform? Well, it's less than ideal in a lot of the same ways that Facebook or Twitter aren't ideal blogging platforms either (though for many people, it is their only blog-like outlet).