you could go to your local library and carry a USB stick.

I don't remember it this way. Nothing else came close to the portable storage capacity of CD (and thus CD-R and CD-RW). The iomega zip drive was still a popular medium, allowing rewritable 100mb or 250mb cartridge. That was the preferred way to get big files to and from a computer lab when I was an engineering student in 2000.

USB flash drives had just been released in 2000, and their capacity was measured in like 8/16/32mb, nowhere near enough to meaningfully move CD images.

Then again, as a college student with on-campus broadband on the completely unregulated internet (back when HTTP and the WWW weren't necessarily considered the most important protocols on the internet), it was all about shared FTP logins PMed over IRC to download illegal shit. The good stuff never touched an actual website.