You used to be able to do something very similar with Perl, right? A bunch of independent scripts that were basically web endpoints? I forget the name of those little scripts...
As a val.town user and former cgi-bin user, I'd say it's a bit similar in terms of how I use it. If webhooks were a thing in the cgi-bin days and I needed a one-off script to run every time a webhook fired, I would have put a script in cgi-bin. Now I'd create a val.
...how is it not similar? A perl script sits on a always-on server, ready to execute. You call it. It executes.