Cyrillic

Because Cyrillic is a big part of international heritage and culture. It is actually one of the first written system of language on the world.

The real reason is that it's because they are international servers, which is why we also see Arabic script, Chinese characters etc. Some of us are pushing for English servers where this won't be allowed as it's very hard for us to distinguish between different players and villages. We just want the same as many countries get with their own servers.