Wow what a blast from the past hearing Onestop.mid again. I used to love that song as a kid, I was absolutely fascinated by the genre switches and how it managed to pull them off.

I think my PC had a Yamaha XGlite on it back then which made MIDIs sound marginally better than the average PC. At least, I remember being disappointed with how MIDIs sounded on other peoples' computers, but that could also just be because I was so used to how they sounded on mine.

I never really looked into why it was written that way before, but it looks like MIDIs were preinstalled primarily so users/technical support could test/troubleshoot MIDI hardware even if the system had no internet connection, and Onestop was particularly useful because it exercised more instruments. Interesting stuff!