Those are some pretty interesting websites of yours! I checked them out to see if they shared some sort of common Kirby look-and-feel, but you seem to put enough emphasis on design to offset any such thing. The projects look very interesting too.

Thank you!

Kirby really makes it easy to create unique stuff, there’s also a nice „Made with Kirby“ catalog here:

https://getkirby.com/love

Why do I need a special API to store my data on the file system? Doesn't the file system have an API? And then my interface to that would be a lightweight layer specific to my application.

Yes, exactly! Copying, renaming, backups, hierarchy - it‘s all there already!

+1 to this. I made some websites for hire in my earlier days and really enjoyed using Kirby. It was simple to setup, simple to host, and then simple to teach the clients how to update the content themselves. I just checked there and one of them is still going strong nearly 10 years later.