TLDR but you actually end up reading even more than the original. I could be wrong and this might actually work and condense a big function but if that is true, why showcase such an example.
You can think of “too long” referring to the time it might take someone to reason out a particularly terse, dense line of code verse the actual length of the code.
I can see something this functionality being useful to explain dense, ungooglable code, like regex, or maybe APL. That said, I couldn't really trust current-generation ML to actually produce a correct explanation instead of being confidently and wildly wrong.