And a reputation boost for the hackers that managed to pull it off.

I wouldn't expect that at all, since the attack doesn't have any security implications other than ‘someone found how to send a lot of requests from routers’, and the target is just one guy with a blog—not a corporation whose job is to serve web requests.

By the way, that's some circular reasoning right there. I asked, what would be the purpose of the DoS attack. You say, it's to hurt the reputation if the site comes down. But why? What is the purpose of taking down the site? Krebs is a security researcher, he's not in the business of running websites, let alone sites that can withstand two million requests a second.

The only security connotation of this is that some guys got a botnet and they flex on Krebs to have him advertise the fact—pretty much like he's supposed to, per his job description.