I don't think competition itself is sufficient in quantity to really be much of a skill-builder. It is a test - a powerfully motivating test, which often helps provide the desire to train and practice in order to prepare for the next competition where one will, without doubt, face highly skilled opponents. And that testing (the competition) can provide pressure and engender legitimate stress in its participants, sometimes even when they are also experienced in real combat. Look up Jim Cirillo and Kyle Lamb's comments on this - sorry, don't have them close at hand.