preform well in as close to a game like setting as possible before taking a chance on a late/non-drafted players. Pre-season is for the guys trying out, etc, not the fans. Coaches want to make sure they're not just practice all stars cause practice has a totally different vibe and set up than pre-season games. A lot of byu guys would have never made a nfl roster or practice squad if it weren't for playing well in preseason games. Hill/Sorensen/etc.

Cutting from 4 to 3 games even hurts to some extent, according to my nephew-in-law who was non-drafted byu player but made it to the last cuts in camp few years ago. New coordinators, etc, need the practice too.