Basically, it's a less expensive and lighter handleabar than a traditional bend for a given reach, drop and width, as it uses less material. Typically, a handlebar this bend is about 6.5% lighter than an equivalent dimension handlebar in a tradtional bend. Less material also means less cost.
These were popular of the early chain store 10 speeds that were basically adapted from light touring 3 speed bicycles with the addition of a dropped handlbar, narrow racing saddle and derailleurs. Some of them even retained the upright touring bar brake levers and hand grips