Whenever I'm behind a corporate firewall, which is often, I find that a lot of third-party services like Disqus are blocked. At those times I would have preferred the site to host it's own comments. Generally speaking corporate firewalls block a lot of stuff by default and the sysadmins don't bother to try and differentiate.

I appreciate the conendrum but I don't think people running the sort of static blog you host on S3/github pages care about overbearing corporate policies.

If I bothered setting up my own blog, I certainly wouldn't spend a bunch of time setting up comments on Lambda just for my two corporate-firewalled readers when I can just use a hosted solution. That is, if I even cared about comments in the first place. There's just much more interesting things to work on, with and without Lambda.