There are two levels of bodhicitta: relative and absolute bodhicitta. What we have discussed so far falls under relative bodhicitta. Absolute bodhicitta is realization of emptiness being the ultimate nature of all phenomena. Relative and absolute bodhicitta encompass the whole of Mahayana teachings; they are the quintessence of Mahayana Buddhism. Without bodhicitta, it would be impossible to practice Mahayana Buddhism. That is how vital bodhicitta is.
~ Depicted from THE RIGHT VIEW - The Three Supreme Methods—the ultimate methods of cultivating virtue and training the mind