Well often when you build something in the software world we are told not to go learn a new language to build it but just stay with the tools you are a master of, so probably this guy was a master of the tools they chose and hence it was not made as software that would have necessitated learning new tools.

However the other thing is that as a system of analog tools it may be able to achieve all sorts of effects that might require a lot of processing power, development time, and sources of entropy for randomization to match. In short I think not just that what was built was easier for the person who built it, but might also be significantly cheaper comparatively.

on edit: of course they can't distribute their machine the same way you can code but that's the tradeoff