The choice of your training split depends on your training level. Beginners need less volume than advanced lifters. If there are only a few sets per muscle group and week, a high split makes little sense, since otherwise only 3-4 exercises would be trained per day and thus no sufficient fatigue of the muscles would be achieved.
The given splits are assigned to the respective training levels according to the current state of science and ensure the best possible distribution of your weekly volume.
A new split can be chosen every 6 weeks, at the beginning of every new mesocycle.