It says it's run by volunteers, and PHP is pretty low requirements, especially for lower traffic sites. Also looks like they'll delete a site with no visitors for a month, which would clear out cruft fast, and they only mention up to PHP 7.3 which was EOL in 2021 so not sure how active they really are.
I feel like it can't be very sustainable if this HN post spurs a whole lot of heavy / experimental users to sign up.
I’m running a static site hosting service and even with that comes challenges with usage and scale.