In many countries, USA for example, the requirement of a degree, no matter what subject it is in, is a prerequisite for employment as a pilot. Consequently they do not have an equivalent of "ATPL's".
In the UK and most of Europe there is no real need for a degree let alone GCSE's to gain an airline job thus the ATPL's are designed to show that you have initiative to read and absorb masses of information and organise your time accordingly. In effect it is a mini-degree style course which negates the necessity of four years at university. As I said earlier in the USA there is no stipulation what subject your degree is in, it is the mere fact that you have a degree that sets you aside. This is not true in all cases but generally a degree is required.
Thus the ATPL's are designed to put everyone on a level playing field and is a measure of being able to have the resiliance to pass the course. I have a degree already and can hardly remember any of the subject matter. It is nigh on impossible to remember every exact fact learned in the ATPL's so just get the pass marks in the bag whichever method you use.