Is the Goal Line Technology Cost Effective?

FIFA finally made the decision to allow for technology to be deployed during soccer matches to be able to tell whether the ball has crossed the line even if it does not get to touch the net. There has been wide demand for the deployment of some mechanism to assist umpires to make the correct decision but this organization has been reluctant to accept any change. At a meeting of FIFA's International Football Association Board last week, the organization made three decisions with the most profound being that on Goal Line Technology (GLT).  The effect of this unanimous decision is that the rulebook will be amended to include two approaches to support referees in making decisions about goals. Interestingly, the statement issued clarifies that the Hawk-Eye and GoalRef technologies will only be used on the goal line and nowhere else on the pitches.

One must applaud the fact that this decision was made after appropriate testing of the technology in order to determine their fitness for the game and thereby reflect evidence based decision making. As a person who watches a moderate number of soccer matches at club and international level, I am wondering whether these technologies are cost effective. I am not privy to any data but understand that soccer is a low-scoring game hence the number of instances in which the technology will be required is less than 10% of all competitive soccer matches. Does this justify the deployment of these machines during on all professional soccer matches? My hunch is that it is not cost effective since only a small number of matches present a scenario that requires a decision that will be improved by GLT .