If you are meaning a Dao blade, then yes, it is merely decoration (I'm sorry, but will you please use correct terminology on the board? When you say broadsword, people think of European blades and get confused). However, depending on the school, there could be some symbolism attached to it, or it might be wrapped around the hand for better grip.

I'm sorry that I cannot help you more, but unless I am mistanken, the people on this board specialize in Japanese arts and fencing. I cannot think of any that have experience with the Chinese arts, much less with double blades.
Fencing Club at UH