The creator of sonic pi gave a keynote talk at my company's dev conference last month. He was pretty clear that it was originally created to help teach children

The creator of sonic pi gave a keynote talk at my company's dev conference last month. He was pretty clear that it was originally created to help teach children programming. It does have other audiences now though. He mentioned that he tried starting with simple games like you suggest but that kids have unrealistic expectations of what they'll be able to do and it leads to disappointment. They can imagine a commercial quality game quite easily but have no hope of creating one. But with music they're excited to be able to make any sound at all and don't expect to be able to create a film score.