Triple Threat Pie?

Seriouseats.com has posted a recipe for one of their top 10 tasty Thanksgiving eats. The recipe is for a Pumpkin-Apple-Pecan pie. But I just don't get the concept. The pie is split into three separate sections and each section is comprised of one kind of pie. Er??? You still have to slice the pie. Therefore, you will still be getting a slice of one kind of pie or at most half on one side and half on another...still separate. What is the difference between having a pie with three sections and having three separate pies except for the fact that you have less pie? And unless you dont want leftover pie (is there a such thing as leftover pie?!?!?) then, really, whats the point?