I love ciphers included on maps, because ciphers are not unbreakable. Personally I think this looks great. I love art maps, maps in other languages and forgotten scripts, but most of all if they can be decoded.

I use a conscript on a map of my own world. I use it for splash, though, not for the entire piece, and it is an English cipher that could be decoded. I think this gives a certain amount of puzzle flair so I enjoy it.