I think KA fulfills a critical niche in the ecosystem of online study materials out there: he actually works through the math in real time on his 'blackboard'.

I think KA fulfills a critical niche in the ecosystem of online study materials out there: he actually works through the math in real time on his 'blackboard'. That's one thing you can't get from watching 3Blue1Brown videos, or reading through textbooks. Personally, I find I learn best when I can work my way through at least three/four different forms of understanding: initial intuition (ideally geometric) of the problem (i.e 3B1B, BetterExplained), the theoretical, proof-based solution you get from textbooks where you can see the derivation of the math concept, and finally, working through problems with a pen and paper. The fourth one is being able to code it from scratch or with the help from a basic library like numpy. KA helps immensely with that third form.