https://www.techradar.com/news/what-is-var-the-controversial-star-of-world-cup-2018-decoded

In a recent press conference, former referee and now chairman of FIFA's referees committee, Pierluigi Collina said that VAR at the Russia 2018 World Cup was "very close to perfection". 

He was referring to the 99.3% accuracy rate the video assistant referee system has had so far in the tournament. If this is indeed the case - and who are we to doubt FIFA's statisticians? - then why has there been so much controversy around the technology that, on paper, has improved the game?