Joy-Con IR camera has another use?

[SonytendoAmiibo]

Peh said:
The Wii sensor bar became obsolete with motion plus. Motion Plus could use blind tracking and pointing. Thus you had to press a button to calibrate it, meaning the pointer went to the center of the screen. This was the case in Zelda Skyward Sword and on the wii U sports remaster for example.

 

But why did the later versions of MotionPlus Wiimotes still have the sensor at the top? The old Wiimotes had to have a MotionPlus module added to the bottom. When the new Wiimotes came out they didn't need the extra module, but they still had the sensor on the Wiimote. If it wasn't using the sensor bar on top of the TV then Nintendo could have just got rid of it when the Wii U came out. But they didn't.