The Xs are present as a visual barrier until the herd knows the boundaries and limits of the harder to see fencing. It's high, not for the giraffe's sake, but for the visitors so if anyone hops the visitor barrier they won't be able to feed the giraffes. Additionally the previous barriers we're terrible and believe it or not, Anuli, one of the younger giraffes at the time, was able to get under the barrier. I personally don't think it's an eye sore and definitely has more to do with safety. Ideally, keepers would like to give the animals access overnight, so eliminating any potential obstacle or way to escape was important.
