Range distance is greater than course distance and practice putting is higher percentage than course putting. The routine, how loose/warm you are, subtle adjustments are all easier when throwing one after the other in same conditions with same look. When putting a million times in the back yard you start to use little crutches that help with consistency, that you may not even be aware you are using. Like nestling your foot on the same little clump of crab grass at your 20 ft mark. Starting your 30 footer level with the height of the close line..... Little visual indicators that help you put the disc where you want, and you may not be aware you are using them. And those crutches certainly aren't there on the course.