why?

i don't think this is needed...

To make "git status" not display the hidden files that start with a dot. For example:

• Vim swap files, e.g. ".NEWS.swp"
• PyCharm's directory ".idea"
• may be also KDevelop's directory ".kdev4", if anyone uses KDevelop for projects in Python

To make "git status" not display the hidden files that start with a dot.

Yes, I know what it does. I think it is way too broad, and adding excludes for the actually used bits is way better.

• Vim swap files, e.g. ".NEWS.swp"

If you get this, then it means that either:

• you are running git status while editing a file (so the swap file will disappear once you finish editing)
• vim crashed, so that leftover file is something you need to handle (recover & delete, or simply delete)

so IMHO hiding it is more harmful than useful

• PyCharm's directory ".idea"
• may be also KDevelop's directory ".kdev4", if anyone uses KDevelop for projects in Python

OK to both, although I'd add them as needed by anyone working on it, when needed