#3 The marketing boost
Real Madrid are comfortably the richest club in the world, and a large part of that is due to their excellent marketing, making them the most popular club in the world. However, La Liga are growing increasingly concerned with the popularity of the Premier League in emerging markets like India and China – the Spanish Federation opening offices in India reveals that nervousness.
Getting Marcus Rashford in would serve as a dual marketing boost – fans in the UK would be interested to see how an English player (and possibly the national side’s talisman in the next few years) is performing, while Asian fans of Manchester United would find a reason to watch La Liga.
In addition, Rashford represents a new generation of stars, as Leo Messi and Cristiano fade with time. Apart from Marco Asensio, Madrid don't have a future star they could legitimately name, although Gareth Bale could hold fort in the coming years.