Both Jeanine's faith and that of the soldiers at Kleos was a blind faith based on a need to have something to hold on to. Becca doesn't seem to have found or believe in any form of faith, not even a faith in herself. Many faiths do believe in higher powers, or even icons (which the heart was to the soldiers) and even the CO as a higher power. Faith is very important in difficult times, ask anyone fighting cancer, you need to have faith in the medication, the doctors, but mostly in yourself and whatever higher power, be that God, nature, prayer. It is what gives you peace. Unfortunately for these characters I do not believe any of them found faith (exception maybe Reno) by the end of the book.