One of the most important aspects of the NFL is game tape evaluation. Coaches evaluate their own team to see how players progress daily. They also evaluate the teams they are going to play for tendencies that can give them an edge.
Players evaluate tape to look for any edge they can get versus the players they will face in any given week. Scouts evaluate tape of college prospects or soon-to-be NFL free agents. Everything an NFL organization tries to do starts in the tape room, because without the evaluation process you can't add a player to your team.