The main point of subversion is that you can tell people which version of the source you used to generate a picture that you published. I created a tag for the code that generated the pictures for TWF 308 - if there is any change in the code, you can still go back to the specific version that generated the pictures and are still able to reproduce them.
If that is not a requirement, there is of course no need to check it into the Azimuth code project - creating a download link on the wiki is enough.
The code for the stochastic resonance page is of course checked in. I also have a local copy that is handled using a local SVN server running on my laptop, because I need this kind of version control even when I am working alone on my own laptop - but that's just me.
When you work long enough on some computer program, sooner or later you will make a change that you don't remember next day until you find out that nothing works anymore. Maybe everybody needs a couple of experiences like this before they appreciate version control :-)