The smaller laptops get, the fewer ports they have room for. It's a common problem, especially on the smaller Apple laptops, which only have two. That's what makes this iPhone cable with a built-in USB hub so smart.
Want three extra USB ports? Just use this cable to charge and sync your iPhone. You can then plug three other devices right into it, saving space and making up for the scarcity of ports on your laptop. It's clever and elegant; it's almost surprising Apple didn't do this themselves.