Enable hand and controller tracking at the same time.

In addition to possibly representing physical objects, Quest Pro controllers could be also used to track legs while using hand tracking for hands. And if more than 2 controllers per headset are allowed in software, I wouldn't be surprised if quite a few people buy an extra set or two for proper standalone full-body tracking. It would be even better if a simplified and maybe cheaper "tracker" version of the Pro controller is made available.