I'm sorry, but this is a perfect example of the difference between design and eye candy. Often, people wonder why I spend $50,000 a year going to design school, when I can learn how to make things that are just as shiny by reading psdtuts.com. The difference is that style is only skin-deep. It's superficial. It's an added bonus on top of design . Design, on the other hand, is the core of the product: how it functions…
Eye candy doesn't help the user with navigation or add functionality but it can make a website look more professional and in-turn more trustworthy.
For e commerce websites getting the users trust is an important consideration and I'd argue eye candy is maybe just as important as the design.
Of course in the case of Hacker News I wouldn't like to see this kind of redesign implemented and would prefer the focus of the site's design to be solely on improving it's functionality and usability.