APs and SAT subject tests give homeschoolers an objective measure to show the quality of their education. Having lots of APs makes your child stand out and shows admissions people they've had an education as rigorous as that offered anywhere. My three oldest each had eight to twelve 5s on APs and 750 and above on eight SAT subject tests, and they were accepted at excellent schools (Harvard, Princeton, Yale, Duke, MIT, etc.) It worked for us!
Maybe APs aren't required, but they sure don't hurt and the public school kids your children are competing against for admissions and scholarships are taking them.