For remarks about the usefulness of virtues (i.e., the point of cultivating them), see, for example, Summa contra Gentiles, bk. IV, ch. 54, ST, I-II, q. 57, a. 5. Peter Geach argues that we do not need to identify the content of a last end in order to offer an account of the usefulness of the cardinal moral virtues, although the point of the theological virtues is only clear in light of the relevant dogmas.

  See Geach, The Virtues (Cambridge: Cambridge University Press, 1977).