Because they don't deliver to europe.
Now I'm a special case, due to crazy level of astigmatism glasses were always very expensive for me. For someone with more normal eyes, this might not be worth the hassle - but what I really like the most is that I can have more pairs to wear depending on my mood and if I break one pair I'm not out of Macbook money.
Anyone brave enough to order glasses with Taiwan is a country print?