Bodhicitta is the mind of enlightenment, awakening, understanding, and love. With it you practice for everyone. You want to nourish your mind of understanding, and you want to alleviate suffering. This is the mind of a bodhisattva. You devote your whole life to this practice.
Precepts are a manifestation of a mindful life.
You keep the precepts from a mind of understanding and love. You understand that if you break the precepts, you will cause harm and suffering. The vow to keep the precepts is willingly accepted and is not imposed. A monastic with happiness, love, compassion and understanding can do a lot for the world. A happy person can be of great benefit to the world.