In Python, every variable is either defined or imported in the file in which it's used, so you always know where to find it. (Assuming you don't do `from foo import *`, which is frowned upon.)
In C++, a variable might be defined in a header or in a parent class somewhere else, and there's no indication of where it came from.
How does this help when trying to determine the parameters a function takes? You have to either hope that the name is descriptive enough or that the function is well-documented. Failing that, you need to read the code to find out.
CMD-click shows you.