Hatsu is "suitable" for Static Sites, but Hatsu itself is not static.

Yes, Bridgy and Bridgy Fed both can do similar functionality, but Hatsu is the only one that is easily self-hosted and doesn't require microformats / webmention.

Web Components to be exact, which reads contextual data from Hatsu's Compatible API. You might also want to take a look: https://github.com/oom-components/mastodon-comments