So what? It's 0% interest. It's incredibly helpful to have easy-access financing to split purchases across a few months.
>even simple things like buying a book through a web site requires declining several offers for paying with credit.
This sounds so specific it seems like you're taking a bad experience with one website and pretending all websites are like this. Most e-commerce sites I've used in the past year offer Klarna or some similar service and all of them have been implemented as just another option in a set of radio buttons.