I don't think there's a reason why he chose to not go with JS, but to show that it's possible with only CSS.
IMO I like using less JS because it slows down the Mobile web experience. JS is super powerful and you get to do cool things with it but you always have to keep an eye out for performance.
I do the opposite. I find more value in the articles as they provide the full picture. I want to read all the information that the author laid before judging or making assumptions.
Also there are plenty of trolls who can troll me if I only read the comments. :/
You can check out https://growthhackers.com/. It's individual stories of what/how they market their company and little nuggets of actionable items for you.
Edit: It was educational, emotional, and enlightening to see what he went through to make the world a better place. Also it's scary to see how much the government can get away with. .. Makes you think.
Key points taken from https://techblog.livingsocial.com/blog/2014/04/02/working-fr...