My D13 graduated from a public HS where half of the grads do not go to college. She took as many AP and Honors classes as possible, to jack up her weighted GPA and class rank, both are (with the SAT) the main factors in admission to NC public universities. The AP/Honors classes were also (probably not incidentally) stacked with the wealthier kids at her high school. And she was able to place out of a semester at her university (though she is still somehow taking 4.5 years to graduate). She also reports HS AP classes are nowhere close to the same as true university classes. May be be a universal observation, just hers.
Still, AP and Honors may be necessary at public schools with wide ranges of student achievement. Especially for grads seeking to go to selective private colleges, who want to know the matriculates can actually do college-level work.