No offense but manual reviews seem to be an old-school thing and it can be costly because they may need to hire more personnel to make things faster or more effective but why can't they just make things automatic like the others? And besides they are not new on this industry anymore. As long as the developer of it is good, the outcome of it is also going to be the same.
We used to offer automatic cashouts (less than 5 minutes) in the vast majority of cases, but we were victims of multiple exploits that caused us to lose large amounts of money, so we decided that all cashouts would be manual to eliminate (or at least reduce) these cases of abuse.
We know it's not ideal, but we are forced to do that for the time being, for our sake and the sake of our legitimate users.