WiiWare games available on Amazon

world of goo

So I received a tweet from Amazon Games today saying that World Of Goo for Wii was available for sale.  You apparently pay Amazon and they give you a download code to use on your Wii.  The price ($14.99) was close to the 1500 points it costs on the Wii Shop Channel, so I was left wondering .. What is the benefit of buying a WiiWare game through Amazon?