>>6249399Blue Elite darts are higher performance than the Streamline darts they replace. Both are designed to function in magazine-fed blasters.
Whistler darts (and most Nerf darts that existed at the time) have a bulbous head, which makes them incompatible with magazine-fed blasters. Streamline/Elite darts are, for the most part, compatible with everything, which is why Nerf pretty much only makes those anymore.
Nerf now has its Accustrike darts, which are one of the most accurate darts you can now get. At some point, I wouldn't be surprised if they eventually become Nerf's standard dart because everyone knows how much the Streamline/Elite darts suck.