Of course. If it seems like a huge waste of time to you, then is must be the same for everyone else as well.

First, Sanborn didn't create a random encoding. He worked with a renowned CIA cryptologist to come up with this, so there's a rhyme and reason.

Second, it's the idea of it all, the effort it takes to break a code and figure out its innards. To me, that counts as one of the perfect examples of hackerdom.

I just don't see the use for it - presumably one could create a random number generator to generate all sorts of codes, and have all hackers be occupied indefinitely? There are so many open problems whose solution would actually increase the body of human knowledge.

Still, if you want to play, play. It probably is a good problem to practice cryptography with.