Why not host it for free through Github Pages? They only host static sites so it's technically quite different to your blog... but if you are only going to be blogging it may as well be a static site IMO.
Edit: I do like how neat it sounds to just query a user's public Gists though.
I've actually been thinking about different ways of adding exactly that to a static site - technically you could have something like a comments form that just writes to a text file somewhere (perhaps updating a Gist with the API you mentioned[1]), which the static site reads from upon page reload.
Sounds a bit inelegant I guess, but could be interesting to implement.
https://devnull.land/github-gist-blog
I only feel sort of bad that I basically use Gist as my data store.