Barça already has the winger it so strongly demanded. A fast player, with dribbling skills, a nose for goal and, perhaps most importantly, a hunger for titles to give everything on the field. Marcus Rashford has been patient and has waited for his opportunity. He has seen how FC Barcelona, throughout the summer, considered different options to strengthen its attack; Nico Williams, Rafa Leao, Luis Díaz, Ademola Lookman… but the Englishman expressed from the very beginning a special interest in wearing the blaugrana jersey. He made it clear that salary wasn't going to be a problem, that he didn't need registration guarantees from the culé team, something that, in these times, is invaluable for the club, and finally his stance has been rewarded. It's a win-win; Flick already has his winger and Rashford the opportunity to redeem himself in a top-level team.
For most Barcelona fans, the loan of the Manchester forward wasn't the preferred option. In England, he has shown himself to be an inconsistent footballer, capable of the best and the worst depending on the season. With some issues regarding his lifestyle off the field. However, my personal opinion is that at Camp Nou, even if not immediately, we'll see the best Rashford again. Let's analyze the reasons to be optimistic about his arrival:

The willingness to wear the blaugrana jersey
In a less romanticized soccer world than ever, it's strange to find players who give up money. They can kiss the badge and swear eternal love to a club, but when it comes down to it, even if they know about the club's financial difficulties, they're going to demand the salary they have signed in their contract. That's why Marcus Rashford's insistence on wearing the blaugrana jersey, despite being aware that in Barcelona he'll have a much lower salary than he would earn with the Red Devils, suggests that he's coming to give everything. If the financial aspect were the most important thing for the English winger, he would never have arrived at Camp Nou, so his insistence on being a culé player for a season, despite the pay cut, is a clear statement of intent on his part.
Flick gets the best out of his footballers
If anything was clear last season, it's that Hansi Flick is capable of getting the best version out of his footballers. Iñigo Martínez became a top center-back again under the German. Raphinha showed an outstanding performance after two seasons generating many doubts. Frenkie de Jong was halfway out of Barça and now he's a key piece in the culé scheme. Pedri and Robert Lewandowski also returned to their prime under the orders of the former Bayern coach. Conclusion; if there's a coach capable of bringing Rashford back to the cause, it's Flick. The Englishman knows it, which is why there's been so much interest in landing in Barcelona.

An ideal system for the Englishman
The formation Hansi Flick usually sets up is perfect for Rashford. Whether in the 4-3-3 or the 4-2-3-1, he'll have the option to stay close to the left wing of the culé attack, where he has undoubtedly been most dangerous over the years. In addition, the Manchester winger also knows what it's like to play as a false 9, so, in a year that could be Robert Lewandowski's last as the blaugrana striker, he'll also have opportunities as the most advanced man.
The only pure left winger
Rashford will be the only top-level left winger in the Barcelona squad, but he's not arriving with the status of a starter. Among other things, because Raphinha's season in that position was outstanding. However, Marcus will bring things to the blaugrana attack that the Brazilian can't compete with. The English striker is faster and has a better one-on-one, so he'll definitely get minutes, especially considering that the international with the verdeamarela can also play as an attacking midfielder and as Lamine's substitute when there are rotations. In a team that lacked dribbling last season, Rashford's dribbles will be welcomed by the fans with open arms.
Soon we'll begin to reveal the mystery that is Marcus Rashford's performance as an FC Barcelona player. For now, as we've just seen, there are plenty of reasons to believe that his arrival at Camp Nou will be a complete success.