Business cost savings are a huge pull factor, for sure (if you counted all the Excel spreadsheet "apps" as software, some old school companies would be in the top 100 apps by usage, easy :)

I also wouldn't underestimate the push factor from the creative folks who are technical enough to "read" code / reason in abstract patterns, but can't write it. Fun definitely comes into that, as does a learning curve that's very shallow and near-infinite.