why not? team can't be valid with one train and nothing in this game doesn't base on one train
some things are basing on one train, for example the GS ... If we now have too trains in a week, we have one training period with one game and one with 2 games which makes gs harder to predict because we need different formulas also it doesn't allow backups on training position for the one game training.
Another thing is the training speed, if you train player X two times a week the player improvement is a lto faster then before, which isn't good.
So if you like to train bot defences you maybe do it, in two weeks ;)