Sorry for not responding in about a year, lol.

I'm trying to figure out what you meant with this:

It is an excellent choice if you want to do detailed documentation, i.e., extensive documentation of all the functions and parameters.

Other docstring styles have a way to document all functions and parameters too. Why is the numpy style better for that?

Actually numpy style docstring has more (14+) section for providing details documention.
You can check it out here.
https://numpydoc.readthedocs.io/en/latest/format.html