In my experience, I see Khan academy being most valuable in a blended setting when the teacher isn't very good (because Salman explains things so well), but als

In my experience, I see Khan academy being most valuable in a blended setting when the teacher isn't very good (because Salman explains things so well), but also over a longer period of time. Khan academy encourages retaining old material in at least two important ways: it makes the old material easily accessible, and Salman's teaching method strongly encourages you to have a better understanding of the concepts behind the math (for me, that's been in proving trig identities instead of memorizing and explaining how the process of multiplying matrices is arbitrary, but it's clearly a fundamental aspect of how Salman teaches).