I clicked that link and was told 'You are in a queue... You will be redirected to our website as soon as possible. There are 16 people ahead of you'. It was like being on hold for call centre! Screenshot: https://s8.postimg.org/6yp8lcs51/Untitled.png
Perhaps its because they often release unique/collectable coins for sale, and so a simple cache wouldn't work. It seems odd to apply it to a static page as well as the shop though.