You're certainly right about abstraction being useful. My fist thought was that the simple-English for autodidactic here would be "self-taught", being aware of unnecessary abstractions, though the subtler meaning is closer to "someone who will teach themselves".
Simply saying "self-taught" wouldn't have had the right connotation: instead of "clever and driven", it would have been, "but what have they missed?" and we would have missed out on this interesting off-topic sub-thread!
I thought there was a difference where self taught would be "I did teach myself this thing" and autodidactic would be "I have the personality trait of continually teaching myself new things." Only one of the dictionaries I checked made this fine grained (and relevant) distinction explicit though.
Having a larger vocabulary allows you to spend more time communicating and less time talking.
Just like abstracting functionality away inside functions allows you to spend more time solving problems and less time (re)writing code.