>>285950083
The drawbacks I'm referencing is loss of tracking when the controllers are close to the HMD and obviously outside of view of the controllers, this has been mitigated by Oculus over time however it's not a perfect solution.
They try to predict your movements out of view from past motions, that's what helps their tracking.

>>285950283
The headset needs to have infrared tracking points on it, Rift CV1 uses these, the camera used to track them is a normal webcam with a visible light filter on it, which helps culling out other lights that could disturb tracking.
Does the Rift S have these tracking points?
Someone could make their own tracking solution for it if they figured out a way to put IR LEDs on the HMD, pulse or refresh them in a certain way and develop tracking for it.

If you use your smartphone, you can check if the headset has infrared tracking points, mainly because phones don't have IR filters on their cameras.
Interestingly the Rift CV1 had tracking points in the rear headband, the HTC Vive seemed to not have these and lose tracking when you turned away from the base stations, the Index does not have this issue anymore, thus you can run an index surprisingly well to how you would setup a CV1, a single base station is enough for a small room thanks to the large FoV of the SteamVR 2.0 stations.