Rainbow flicks are for screwing around in training and impressing your friends when you're 12 because they are proof that you are good at soccer. They are not for real matches.
That is unless you are Admir Catovic. He pulls them off in real matches to get past defenders.
One rainbow flick and he's off, leaving a dumbfounded defender in his wake. Hopefully they do video sessions in the Finnish league because it is important that he get a standing ovation from his team, while the opposing defender gets clowned on by his. If not, what's the point of sports?