Ok so a bad performance on the ball now means he's useless? James has his uses, wins loads of free kicks, takes loads of hits and gets up every time, runs his ass off and works incredibly hard to put a shift in defensively which balances out having Rashford, Bruno, Greenwood as 3 of the other 4. Putting a kid who has 0 muscle on him would not only be a risk to be detrimental to himself with all the kicks and potentially getting injured as his body isn't ready for that, but also be a detriment for the team as it wouldn't have enough balance in the attack between attack and defence.
Again, Amad Diallo was not bought for this season. He wasn't bought for next season. He was bought because he has supposedly world class potential, but that doesn't mean he is world class right away. Just like when Sir Alex would start Park Ji Sung ahead of Cristiano Ronaldo often times during Ronaldo's first year or 2 when he was a teenager. Amad Diallo is literally a teenager with the body of a kid who has had virtually no exposure to professional mens football. So no, it's not wasted money. It's just he was bought to be a long term member of the first team, and not an immediate member of the first team.
People in here need to relax ffs.