BetterTime is just a wrapper for Unity’s Time class. The thing with their class is that every call has a marshal overhead since it calls their native C++ code. Since most of the properties don’t change as often as they’re called, it is worthwhile to cache them. This is what BetterTime does in the background.
It is a small performance benefit, but it is totally free as it’s just about writing BetterTime instead of Time and everything remains the same.
Every UnityEngine.Time property is wrapped and the API stays the same. Just call BetterTime instead of Time.
Eg. instead of:
transform.position += velocity * Time.deltaTime;
You should write:
transform.position += velocity * BetterTime.DeltaTime;