These are not normal account signups, they are signups to become an associate member (https://join.osmfoundation.org/) which can vote in foundation elections.
I wanted to like Hugo (especially with its ridiculous speed compared to Jekyll), but I found that any time I wanted to do something slightly unusual I had to spend far too long finding what template file name I was supposed to use, mostly by trial and error. With Jekyll I just specify the template name in the front matter.