Actually I think several of the large Taiwanese monasteries do insist on high school.
And many of the monks and nuns have BAs and even graduate degrees. If your level of education is higher, you will have access to a broader variety of opportunities in the monastery. If you don't have a degree, your options will be very limited. Chinese culture really values education. A degree would be less of an issue at a Theravada or Tibetan monastery.
A foolish man proclaims his qualifications,
A wise man keeps them secret within.
A straw floats on the surface of water,
But a precious gem placed upon it sinks to the depths