Depends on so many things. Acceleration is usually more important,especially for possession based teams. However, for counter attacks you need top speed. Wingers also need top speed. Iniesta, for instance, had great acceleration but poor top speed, so he couldn’t play well as a traditional winger.
Neymar and Messi are not the fastest over 15 meters. It’s hyperbole because they are both top three players in the world. I’d wager Sterling is just as quick and neither are as quick as Lennon was. Speed with ball control, agility, stoping ability and end product gets you there. That Traore fella is lightning and can also dribble, but his end product is running the ball out of play.