So you don't have a problem with all of the other magical teleports in the game, just for the battlefields? It could have been worked into the story better, but I think it was designed to be a distinct area.
What other teleports are you referring to? I think the pyramids are cool, and don't forget they are an object you have to carry around, and activate in order to teleport.
The battlefields teleport doesn't require actually carrying around the keys, you just touch a key and then after that you have the innate ability to teleport there... Bit cheesier.
