Can the Buddha hidden in the void be used as an avatar?

You can use it as long as you remain in awe. Taking Buddha as the head is a way of giving. Mahasa, vanity bodhisattva and boundless bodhisattva specialize in wisdom, merit and wealth. Because respecting wisdom, merit and wealth is as broad as vanity, it can satisfy the good wishes of all practitioners in the world and make infinite benefits for all beings, so there is this vanity to hide the holy name. The bodhisattva hidden in the void is a symbol of honesty and wealth. Using the Buddha hidden in the void as an avatar can save money.