Spring camp is usually used by coaches to hammer drills into players. The players hardly see the plays until well into fall practice. So both sides of the ball are running boilerplate plays only designed for practice, not really to take advantage of anyone. Also consider that a lot of players on the field barely see playing time in the regular season. Scrimmages, especially in the spring, are pretty pointless to get an idea of how the team is really going to operate on game day, but are great practice for the team because the coaches get to put players in positions they normally don't see.