Comment by IshKebab

Probably the fact that it's a pretty terrible idea. It means you take a normal properly typed API and smush it down into some poorly specified text format that you now have to write probably-broken parsers for. I often find bugs in programs that interact with `/proc` on Linux because they don't expect some output (e.g. spaces in paths, or optional entries).

The only reasons people think it's a good idea in the first place is a) every programming language can read files so it sort of gives you an API that works with any language (but a really bad one), and b) it's easy to poke around in from the command line.

Essentially it's a hacky cop-out for a proper language-neutral API system. In fairness it's not like Linux actually came up with a better alternative. I think the closest is probably DBus which isn't exactly the same.

Maybe something like FIDL is a proper solution but I have only read a little about it: https://fuchsia.dev/fuchsia-src/get-started/learn/fidl/fidl