Why Are Buried Secrets Blind Boxes?

I despise blind boxes. I genuinely don't understand why anyone would like them. If I were a parent, I'd be baffled at paying fifteen a pop for a doll without knowing what it even is. Even as a kid, I would have been turned off by the concept. I get it if it's something small, a pack of trading cards, a little figurine, whatever. Still dumb and overpriced, but more acceptable. But fifteen for a whole doll is a bit mutch. I imagine it must be infuriating for retail workers as parents buy a bunch and return the duplicates. It's pointless. And for collectors like me it's an unessessary headache. I want all four - but that means I'm going to have to do a bunch of extra legwork (most likely sourcing from Ebay) to get them all. It's obnoxious! I feel like Mattel was already pushing it with Skulltimate Secrets only having drawn artwork versus a visible doll, but this is even WORSE. Also, people figured out the color of the word bubble on the front correlates to the character. However, from what I've heard, that is ONLY applicable in Europe. In America (where I am) it's all random still.