Back then internet wasn't freely available. While I don't know the situation in Taiwan back then, but it getting it on a floppie might have been the easiest way. A physical thing that still cost money and time to write. Selling cheap to the pirates still made them some money, the pirates saved time spent writing drives, and they could make sure the customers got official boxes with correct contact information on.

Where I come from you went and bought PC magazines bundled with floppies and later CD that had a demos and shareware products on. The magazine was often not the interesting thing in the bundle. So calling it ripping off is a bit harsh, the pirates were providing a service. Even with access to the internet, surfing the web did not work the same as it do today. Without an address it could be hard to find pages.