It's all in the details. As it never mentioned anything about what the cable is made of, what gauge it is, and what is the purity of the copper inside. I wouldn't be surprise at all if the sound quality didn't improve. From looking at the listing, it would be as if buying the stock cable again, if not worse. It is a good thing you only spend $15 USD for it, otherwise, I would say you got ripped off.
Actually, I bought this cable so I can use it for awhile then if it breaks I can going to use the connector to build my own cable.
The connector with gold plated is around $20 USD, so it's a good deal :)
But I like to know the spec on Fiio SE1 cable, anyone knows what N grade it is ?