I want to know an advantage of these function when picking world objects, and which one should I use for certain scenario.

I have tried these func and these are results from a small test.

World.objGet() / World.objGetAdd()
Uses OBJ_TYPE, IndexToFlag not allowed?
This will only pick object if object's position (center) is within picking shape.

PhysCutsCallback with Physics.cut and/or Actor.cut
Uses AG_GROUP, IndexToFlag allowed.
This will pick object if their actor are cut with picking shape, also allows PhysCutsCallback method overriding for extra filters. OBox shape also allowed.

Maybe there's other way as well, but I found
I'm currently use Physics.cut, which I think it's more versatile for overall use.