As other posters have pointed out, why not do it in HTML from the start? It's more simple and efficient than this -or any- framework. Just drop the ol HTML file on your server and away you go!
I understand that the supposed "real" utility in this would be when you want to do JS-y things in HTML (auth, API, hand state, etc), but they don't show any of that on their showcase site...so...yeah.
But this example does showcase a few things you don't typically get with a single vanilla HTML file:
- JSX + reusable/shared components
- Multiple URLs / pages
- Tailwind
Clicking around with the Dev Console open and watching the pages in Sources was enjoyable.
Someone mentioned rails, and rails have a lot of facilities to set correct cache headers for assets (css, js, images etc) and for dynamic content (for logged user in and/or for pages that are dynamic but public).
If you're deploying static files via a vanilla web server, you also get a lot of that for free, via the file meta-data.
I would expect a framework for publishing sites to showcase a minimum of good caching (client cache, ability to interact with a caching reverse proxy like varnish - and/or a cdn).
I'm not sure Deno(the service, not Deno the language) are actualy proposing a model - similar to Cloudflare, for example - where you have your infra somewhere and they only host the "edge", in a CDN, or spread around the world.
This application is generating HTML on the server, but so does PHP. A Web site backed by a PHP application is the antithesis of a static site.
If you can elaborate on how statically-served HTML would render orders of magnitude faster than server-sider-rendered HTML with a similar response time, I'd love to hear it.