It really is a great way to introduce a narrative into the code. Too much of reading programs feels like taking a look at either just a plain convoluted mess, or an index that someone put together for another larger work. (This is especially true for pieces where someone makes a lot of single use functions. Sure, the pieces may be "self documenting," but it is almost akin to just seeing a bag of screws. You know what they do individually, but you don't know why they are there.)
If you have the time, take a look at any of Knuth's programs[1]. Obviously, they are not all immediately approachable, but render them to pdf and give them a try. You'll hopefully be surprised just how much you do pick up.
The only downside, to me, is that I become less concerned with modern trends of long variable names and abstractions that "self document." These are still great, of course, but they don't go nearly as far as knowing the narrative of why a piece of code was written.
I personally have been using it to document the more complex code that I write -- that is, the code that I have the most trouble explaining to others. I'm quite happy with the results for my collision detection library. [1] The library itself serves as a basic tutorial on collision detection, and I've used it myself for reference when I step away from the code for a while.
As I said elsewhere in this thread, I've been exploring using it as a replacement for my hack of reading git logs to better understand codebases. Git logs are immutable, whereas a literate format can provide a cleaned-up history of the evolution of a codebase. http://akkartik.name/post/wart-layers
If you have the time, take a look at any of Knuth's programs[1]. Obviously, they are not all immediately approachable, but render them to pdf and give them a try. You'll hopefully be surprised just how much you do pick up.
The only downside, to me, is that I become less concerned with modern trends of long variable names and abstractions that "self document." These are still great, of course, but they don't go nearly as far as knowing the narrative of why a piece of code was written.
[1] http://www-cs-faculty.stanford.edu/~uno/programs.html