TOML is basically a formalization of the old INI format, which only existed in ad-hoc implementations. It's not really a "language", just a config data syntax like JSON. It doesn't have major footguns because it doesn't have a lot of surface area.
The various features it has for nesting and arrays make it convenient to write, but can make it harder to read. There is no canonical serialization of a TOML document, as far as I can tell, you could do it any number of ways.
So while TOML has its use for small config files you edit by hand, it doesn't really make sense for interchange, and it doesn't see much use outside of Rust afaik.
I believe TOML can always be serialized to JSON. And TOML is in the python standard library in newer pythons. It’s also used as the suggest format for `pyproject.toml` in python
The various features it has for nesting and arrays make it convenient to write, but can make it harder to read. There is no canonical serialization of a TOML document, as far as I can tell, you could do it any number of ways.
So while TOML has its use for small config files you edit by hand, it doesn't really make sense for interchange, and it doesn't see much use outside of Rust afaik.