This marketing site fails to answer the most important question: What's the value proposition? Why should I care writing "Pythonic" code?
1. The idioms are generally the most elegant way of using the language, so if you use them, it means that you will use the language in the most efficient manner ("with" statement for file handling is one example);
2. It's easier for other people to work with your code;
3. You feel good knowing you're doing the right thing.
4. Idiomatic code receives more attention from the Python core developers and might become faster in the future (for free!).