This actually got me thinking. Do we really need CDN? This is one of those thing we take and use without actually thinking whether we could do without it.
CloudFlare will proxy whatever site you configure, even if it is static.
Static websites will get the best speed boost from locally served assets (much reduced latency from the local POP) because the page itself can be cached (presuming headers on origin site are correctly set). Especially for page requests from international users.
Sorry, I wasn't clear. What I meant was that since HN is dynamic its dynamic content is not usually cached. I mentioned specifically "dynamic" sites on my parent comment because as of this month Cloudflare can host static pages.
Don't take my word for it. Test it for yourself: