Having ATPL (note: f is nowhere to be seen in it) is legal prerequisite of becoming designated PiC (sometimes mistaken for captain, which is rank) of an aircraft requiring more than one qualified pilot for normal operations. This is almost universal, the only exception I can currently remember was the deceased Yugoslavia, which issued CPL first class that enabled the holder to exercise PiC privileges on MPAs with less than 20t MTOM.
However, simply having ATPL may not be, and most of the time is not, sole condition for becoming a captain as companies do set higher standards (minimum total time, minimum years with company or both) for promotion.
Anyway, I think this thread is wind-up. That someone in transport category aeroplane's RHS approaching 1500TT is so disinterested in aviation that he knows not what ATPL actually is, really beggars belief.