for loop the difference

[buran]

Your code is definitely better, with the recommendation to use more descriptive names like genres = ... and for genre in genres: instead of i. We even have special thread in Tutorials - Never use "for i in range(len(sequence)):"

I looked at the article in your link - note that it's just an example, i.e. they show the more pythonic way first and they also show what you can do too using index. In other words I would say it's just for educational purposes