Offerings go towards simple living expenses, teaching, and future publishing of Buddhist translations and writings. A major aspect of monastic life is that monks are required to live without handling money. In the west, your offerings provide support in a culture where traditional alms rounds are not practiced for the daily meal, for example. In America, these traditions are culturally very difficult and don't work so well. Donations help venerable to live by traditional ascetic principles, and teach Buddhist philosophy and meditation in a mostly non-Buddhist culture.