Yah, i know that CA3 is a bit low for the main squad in higher leagues, however in low ranked leagues might be enough to make them play and in higher leagues a player CA3 can play at least 30 minutes.
In the meantime, a recently promoted youth gets CA1 or CA2, make a CA3 play against a CA1 is too much difference, even more, a player CA3 surely has at least low experience.