In reply to Ryan Peacan.

WordPress must be running somewhere?

Yes, but plugging into that negates some of the benefits of a JAMstack site. The goal is to totally separate the frontend from the backend, so that there is no risk of frontend traffic interfering (maliciously or otherwise) with your backend. By plugging comments directly into WordPress itself, you lose that benefit.

Your cheap host solution would work, but it wouldn't scale very well and scalability is another huge benefit of JAMstack'ing things.