These holes are commonly called direction holes. They mark the effective sound generating end of the flute because this point is where the vibrating column of air that creates the sound stops vibrating. Some think that the added barrel length beyond this point adds a mellowness to the tone of a Native American style flute. It does make a Love flute look longer. I don't notice much difference in tone with or without these holes. I don't particularly think that my flutes needs the added length to look impressive so I don't use them.