There are scenarios where people either don't have a hip tracker or don't want to deal with some of the common annoyances of it (such as occlusion). This 5 point tracking configuration would allow users to use their HMD, controllers and leg trackers in VRChat, without requiring a hip tracker. This should be feasible for some as these points are the end effectors in an IK rig, meaning that the hip estimate should be good enough for most people. Those who would want a better hip of course would use an actual tracker.

Attached is a demonstration to show that this tracking configuration can work, which uses a SteamVR driver (Augmented Hip) I wrote.