The most important reason is to educate sanghas who will benefit the sentient beings and flourish Bhuddhism in the world.
Till now,numerous saints all obeyed the teachings, upheld reverently and finally got enlightenments after Sakyamuni Bhuddha. The lineage is passed down by them. According to it, we foster and educate the sanghas to let them practice Bhuddist and prepare their career consummately.
Also, we bear all the daily costs, including food, clothing and living.