It generates articles only once. So once it's generated, it never perish.
Logic looks like:
If article exist -> show it
If not -> generate and save
That could be the thing behind it being so quick.
Cloudflare workers have 1ms cold start.
I feel like I have some minimum latency "priced in" to my expectation when I click a link on a static site, so yours feels uncannily like it's somehow able to anticipate my clicks, adding to the surreal atmosphere.