Because a goalie can still cover the high part of the net, while maximizing coverage down low. Remember, a puck shot above the crossbar of the plastic goal frame at the top of the crease will go over the net on the goal line.
When the goalie is square to the puck and centered in the opening, this style maximizes coverage.
When the angle changes, the dimensions of the “True” goal shrink even more. 3’ X 4’ Rope are aligned with a puck on the boards at the blue line.
From the view of the puck. Notice the position of the hands.
Butterfly position to maximize coverage, but beware.
There is actually more net open up high on the short side. Rope touches plastic goal frame on far side, but not the short side.
A view from the other side showing more net up high on the short side.
Shot aligned with in-zone face-off dots. 3’ X 3’
A view from the puck’s perspective. More net up high No net showing