I am not a head coach and don't have skills as well as vision of a head coach but in my opinion, I don't see any good contribution of Rashford for Barcelona. It's not like a necessary transfer that can help Barcelona improving their squad more. If it is done, it will cost Barcelona more money while with their exisiting financial crisis, they must self-limit money spent in order to boosting their financial crisis resolvement faster.
I don't think so dude, there is no doubt Rashford is a player who is talented and hardworking. If he gets enough support from teammates, especially in the midfield area, he has the capability to net bunches of goals. if you look over his fitness it is also kinda good, in the 2022-23 season, we saw Rashford score 17 goals with 6 potential assists in Premier League. So if he could adapt with skill with Barcelona players, he will also play well for Barcelona.
afaik he has long wanted to play in Barcelona. so there is no doubt He will try his best to perform well with Barcelona. If Rashford somehow able prove his ability then there is a possibility they will buy him next season, if his performance somehow decrease then I think Barcelona will not buy him.
However, Rashford's chances of getting a place in the starting XI are low. If Rafinha or Lewandowski do not get injured then probably we will not see Rashford in the starting XI. with this short playtime on field oI don't know how much Rashford can prove his ability in such a situation.