Must armature be at origin before posing in pose mode?

In this youtube clip “The making of Sintel : layout process sm” at ~06:31 and at ~09:55 Levi says you should leave armature object at zeroed transformations (translation 0,0,0;rotation 0,0,0, scale 1,1,1) or else it will cause problems. you can then in pose mode put your rig anywhere in space.
He unfortunately doesn’t explain why it will cause problems if you don’t do it this way.
So what problems he is reffering about? Thanks in advance!