This is much ado about nothing.  trump isn't smart, informed, or thoughtful enough to have made a considered or strategic decision about this.  What he was doing was basking in his win, feeding his ego because if you have  no centre, this office will do this to you.  From news reports someone in his group facilitated the call, either knowingly (they have their own agenda) or unknowingly.  This is why ignorance-ego mix in such an office is dangerous.  He ignorance-ego will make him easily led.  I suspect that his inability to reason/think/take in complicated information is the reason he wants his children around him, they'll explain everything once his 'cabinet' is out of the room.