I can understand the length argument. Everyone has different layouts in their homes, offices, etc and sometimes the supplied cable doesn't cut it.
With that said, I do like the design of using a USB cable and a separate plug. This gives you quite a bit of versatility. If they only supplied you with a standard cable with attached plug, you would have to purchase the USB separate (or vice versa). Either way you are buying an extra piece.
I have noticed that most modern hotels have upgraded the socket configurations in their rooms to allow for plugs near the night stand or even USB charging wall plugs. That is very helpful.