> it would really be more complicated in C if a and b were actually strings or lists
You don't event need strings or lists for that. Just imagine bigger numbers for a and b. Arbitrarily long integer addition is not a native language feature in C.
Joking aside: these are not catch-all comparisons. Nor is the article. But Python is mucher slower and much safer than C. It's easier to start in Python than in C.
How much more, though? The conventional wisdom here seems to be that it's worth taking the unavoidable performance hit of dynamically typed scripting languages because the productivity boost to programmers balances it out... but I don't believe I've seen that productivity boost measured. Once you know what you're doing in C, you can do that same things you can do in Python. There's some (fascinating) syntactic sugar in there, but Python can easily be just as incomprehensible as C.
You can become productive in python faster than you can in C. My background is the natural sciences and on reason python is used a lot in these fields is it's ease of use for people not coming from a computer science/engineering background.
a+b in Python adds two numbers. a+b in C adds the numbers if their sum is below a certain size, if not then it's undefined behaviour and destroys the security of your entire program.