Meh, you can get carbon nanotubes out of soot too [0], they occur in any high carbon and high temp environment. Their existence in something is not proof that metallurgy is advanced in any sense, just luck.
European and Japanese fighting styles are also very different, as the katana is made with much more brittle steels [1]. In Japan, the block is not hard and the other blade has to slide along your's to not break the sword.
You use Damascus steel if your steel is of poor quality or you don't have the chemical know how to make good steel. You do what you can with what you have.
Still, swords cost a lot to make and end up as a status symbol. Look at the Japanese officers in WW2 [2].
European and Japanese fighting styles are also very different, as the katana is made with much more brittle steels [1]. In Japan, the block is not hard and the other blade has to slide along your's to not break the sword.
You use Damascus steel if your steel is of poor quality or you don't have the chemical know how to make good steel. You do what you can with what you have.
Still, swords cost a lot to make and end up as a status symbol. Look at the Japanese officers in WW2 [2].
[0]http://www.sciencedirect.com/science/article/pii/S1044580305...
[1]https://history.stackexchange.com/questions/5729/how-do-tama...
[2]https://41.media.tumblr.com/ab40ee35c57c64a56570035045f61c4e...