That's because there was malware that spread via autorun, which is rather harder to do with read-only media, even if it's emulated.

When the system was designed, the way to get a CD to an end user was to spend at least in the range of ten thousand dollars to get discs mastered and pressed, and then convince physical stores to sell them for you. As well as being a lot of effort, there'd be a clear paper trail. You couldn't just burn one and leave it in a parking lot.

Even when you could, viruses didn't tend to spread that way.

Not all malware is viruses, which brings us back to the subject of the article.

And the "u3" flash drives that did this were a hot commodity for a little while!

Then came the iODD and the IsoStick...