When most people think of eating cereal, they think of getting a box and pouring out some to eat. That’s fine. But if they wanted variety, they usually had to get a variety of cereals and rotated when they ate each. Even then, if you were limited on cereals you were willing to eat, or could eat, like the generally bland, but healthy ones, there’s not a great deal of variety.
Now, what if you were to buy a variety of cereals, but mixed them some of the time you ate them, and not some of the other times? You’d have more variety for the same cost, and some varieties you can’t buy in stores.