It seems to me that the main benefit of the deep pan is to keep the filter from being uncovered during hard accel/ decel/cornering. Without the filter extension, that benefit is not there. IMO, If someone is using a deep pan, a extension is not an "obsession" but a logical addition.
I was always under the impression, the deep pan and extension, was so you could run the fluid level (still same number of qts) lower, and reduce windage, and "churning"/foaming.