It also funds Pell Grants and other programs aimed at low-income or special needs students. So abolishing the Department of Education won't affect you unless you're one of the 17,000 employees who work there, or are a poor or disadvantaged child.
Speaking of the latter, in 2010 the company I worked for volunteered to help out one of the public elementary schools in the 7th Ward in New Orleans. I'm not sure if any of the painting I did that day actually helped anything because you're not really supposed to paint when it's below freezing, but one of my coworkers happened to have a dyslexic daughter, and he was able to figure out that one of the problem third graders was dyslexic. And the teacher actually cried because they just couldn't figure out why they couldn't teach this one otherwise bright kid, but armed with an informal diagnosis they could at least look for programs to help him. Without some kind of program that kid was fdoomed: no money, no healthcare, dysfunctional family, dyslexic. If he didn't get into some kind of special ed program or tutoring I'd be astonished if he's even still in school. Guess we'll just replace the Department of Education with the Department of Corrections.