I'm just feeling curious right now. When tracking is disabled, do the controllers send accelerometric data to the device? Does it affect controller battery life? Could that data be used? Perhaps by developers? What if there could be a hypothetical Wii emulator? The Wii motion plus attatchment allows the Wii remote to send gyroscopic and accelerometric data to the Wii console. In theory, that could mean a Wii emuator that doesn't require tracking is possible? That is just an example of how this power can be harnessed.
I don't know what or why I need to know this. I'm not a dev or anything like that. I just have an engineering mind that told me I need to know simply to have the knowledge. I'm also writing this at 03:30 so maybe that has something to do with the seeming randomness of this question.
Please discuss if you want or just say whatever you think.
When camera tracking fails, IMU data (accelerometer, gyroscope and magnetometer) continues to be used.
For example, I was playing beat saber on the quest outside yesterday and the sun was blinding the cameras. My left controller (sun was to the left) locked in the air, but I could still turn it around (rotation tracking).