There should be replays in soccer. There are various reasons for this. Soccer is a well-known sport played by hundreds of countries and World Cup is considered as one of the biggest sporting events. Due to this, accurate decisions have to be made by the referees. However, often referees make mistakes and are not always there to see if the player was 'offside' or not. In this case, replays should be there to confirm it. This would make the sport much more reliable and enjoyable to watch. If there weren't replays during the World Cup, riots would happen all over the globe for 'disallowing goals' or catching an onside player offside.
The use of repetition would solve the referees fail decision. But that is not the point, that fails make us feel a lot of many feelings that maybe are not good but with out them the games would be boring. The game would be very slow, and not dynamic. Also this decisions give us something to talk about, after the game everyone is talking about that action that change the game.
The speed of the game would be affected. Soccer is a 90 min. Game with barely any pauses, stoping the game for a replay would affect the fluidity of the game. It would create more problems between the players and the referees. The referee would no longer be in control of the game and their job would be no longer be respected.