What is the importance of -- in terminal?

Question

Say I have a command to install pygame :

pip install -- user pygame

What is the importance of "--"

Answer 1

It tells pip that what follows is an option, not the name of a package to install.

Answer 2

'--' is for long options
'-' is for short

for example:

gcc test.c -o test

and

pacman -S --noconfirm vlc