For the simple reason that they say Campagnolo on them, and most likely bought by folks who don't yet know about them or by folks that don't care about how they work. Name recognition, plain and simple. If I saw them on a bike in a thrift shop I'd get the bike if the price was otherwise in my buy it anyway range. If I was selling a bike on CL or ebay I'd mention them, again simply for the name recognition. But in reality if I wound up with a set then they'd probably become wall art of some sort now that I know of how they function (or don't).

(Which reminds me that I need to figure out what I have at home and see what level that set is at.)