What's the use of UPrimitiveComponent::GetCollisionShape

It seems the function is useless.
I try to make a coordinate axis like the editor’s in my game. So I let my component inherited from the UPrimitiveComponent,and I have drawn the axis out.Now I am trying to make the collision of my comp .At first I think I just need to override the UPrimitiveComponent::GetCollisionShape, but this way doesn’t work.
I wonder the use of this funtion and how I make my component’s collision out(Now I just have drawn my component,but it has no collision).