Seems clear to me but I've been watching this project grow for a few years now. If you read the brief introduction, motivation, and quick start on the homepage what do you think the project does?
> why would you want to use something like this
I would agree that part wasn't clear to me either, at least not right away. When compared to something like a SPA the state has to persist on the server while an ephemeral state exists on the client. With HTMX the state only needs to exist on the server. If this sounds like the MPAs of yesteryear, it is. You render the HTML using the frameworks/tools/languages you fancy. HTMX provides custom attributes you can use to update content within a page without having to reload the entire page.