Why do people make such a big deal about backwards compatibility?

[Hedra42]

Money saving and convenient. All the old Wiimotes work with the Wii U. So there were 5 kids playing the Wii U here this afternoon. One on the gamepad, two with the Wii U Pro controllers, and two on the old Wiimotes. They played Rayman Legends, SSB Brawl and Tank Tank Tank.