The same reason you'd use it for a non-static site; to ensure that visitors to your site are getting your actual site content and not something else(i.e. avoid a MITM).
If you had a purely informational site and it listed phone number, address, or heck even a bitcoin address, wouldn't you want to make sure that your visitors got the actual site and not something malicious?
There was a story last week about a guy who's ISP was inserting content into web pages. I can't find the link as I think it got lost as a result of the HN server crash. SSL prevents crap like that.
Are you referring to “I fought my ISP's bad behavior and won”[1]?
If so, in that case the ISP altered DNS results to point to its own HTTP server and redirect to the real one with a modified URL. SSL would have helped a bit, but the first problem is that DNSSEC isn't more widespread.
