Jekyll is also much easier to maintain, with it's built in web server for testing, and static page generation, using a github repo is so simple it's stupid.
Judging by the number of Wordpress blogs that become unresponsive when they hit the front page of HN, it doesn't seem like it's too easy to keep them running with any traffic (or at least, people seem not to be doing it).
Yes, WordPress requires a database; but when has this been an issue for business people, real bloggers, etc. to find a decent host with database support?
Sure, Jekyll sounds like a more efficient solution, but most people don't have a "pain" point when running WordPress - at least not one that can't be solved with a plugin. (Most people)
Jekyll is also much easier to maintain, with it's built in web server for testing, and static page generation, using a github repo is so simple it's stupid.
Jekyll is the way to go.