There's a subtle difference between being a regular coach and a manager in football and Zinedine Zidane will experience how big that difference is next summer. According to COPE, the French coach will be deciding the signings and sales for Real Madrid, meaning that he will also be the Football Director from now on.
Jose Mourinho was the only manager that had that kind of power within Real Madrid. With him on board, Real made meaningful signings that made sense with the roster assembled back then, unlike what's happened in the last few years.
It's a bit surprising to see Florentino Pérez giving Zidane the power to make big decisions given the lack of experience the Frenchman has, but it's also true that this is the best the club could have done to show Zidane trust. He is the one working with the players and he is the one who knows what moves could help the current squad.