On the other side, the Oulipo school of writing believes that writing with apparently arbitrary constraints improves the results.
Oulipo games are about helping creativity.
The best explanation I've seen for this phenomenon is that it works by forcing you to avoid cliches. For example, if you have to fit your words into a fixed meter, you can't just use the first phrasing that comes into your head. You have to hunt around for alternative words that fit the pattern, and in the process you most likely come up with something original and surprising.
I don't think this applies in the same way when you're writing a program. The goal there is not to be original and surprising -- if anything it's the opposite! You want to convey the meaning of the code to the reader as clearly as possible, and if it uses an idiom that the reader has seen before and can instantly recognise, then so much the better.