They just clutter classrooms and distract serious students.
Suggestion:
If a child ( of any age) takes the SAT, ACT, or GED exam and earns a high enough score, then he should be able to go to his local high school and be awarded an **official** high school diploma. Any funds that would normally go to K-12 schooling should then be available for college tuition or trade school.
A high enough score on the ACT, SAT, or GED is **literate** and **numerate**! Just putting in time at the local high school and collecting a diploma is worthless if the child can barely read and is innumerate.
I once dated a man who graduated from the highly competitive Stuyvesant High School. Many of those kids are completely wasting their time in high school. They could finish college and be well on their way to advanced degrees in 4 years spent in high school. Drive by you local high school, and my bet is this is also true for the top 5% of students in that school.
My homeschoolers entered college at the ages of 13, 12, and 13. By the age of 18, two earned B.S. degrees in mathematics. The oldest went to night school and traveled the world representing the U.S. in a sport. He still finished a masters degree at a typical age.