Welcome from Texas! My grandfather was ground-crew for a B-24 Squadron over in Italy. Couple of nice planes, those -24's and -25's!
From what I understand, the point system was used to determine who went on leave back to a rest-area in Australia or NZ, who got to go back behind the lines and "ferry" a new plane forward (usually loaded to the gills with booze), and after the war ended, a similar point system was used (based on time-in-theater, medals, etc) to determine who rotated back Stateside first. For the pilots, points were earned based on missions flown, difficulty of mission, etc....so those golden "ferry" missions were really looked forward to!