Joy-Con IR camera has another use?

[SonytendoAmiibo]

RolStoppable said:
Nope, that's not what it is for. If it was, the left Joy-Con would have an IR camera too, otherwise a game like ARMS would give you inferior controls for your left hand.

But the two Joy-Cons are a matched pair, and communicate with eachother and the Switch tablet. Only one camera is needed to keep the system from drifting.