Here's a great video of Daniel Shiffman, an assistant professor at NYU's Interactive Telecommunications Program*, talking about why everybody should be learning to program. He uses Processing as an example of how programming can be an artistic medium. There's a fundamental point in this video that seems basic but I think is really strong, which is that computers shouldn't be an end unto themselves, they should be used as a means of creation. While Processing is only one tool in the digital creator's toolbox, I think this hits on what's great about it. It's structured around the goal of requiring only the most basic amount of programming to create something really compelling. The magic of computational or generative art is how a relatively simple algorithm can create something much greater than the sum of its parts.
* Man, three months ago I knew nothing about ITP, and now it's popping up everywhere from the books I'm reading to the people I'm working with to conversations with friends. If the stuff in this video is exciting to you and you're in the market for a graduate program, give it a look.