its still better in a sense. usb storage devices all have an internal "mini computer" that run their own code and have access to the USB bus of the connected computer, with the ability to even present themselves as a keyboard, a network adapter or a lot of other things. that's not a good idea to plug in to the hospital computer after it was given to the patient, and it is also not the best idea to just plug these in at home.

optical media on the other hand does not store code that is executed by the drive.

the problem is that pendrives have a firmware, and too much capabilities, even when not accounting for errors in hardware and code that participates in making it work. some of them (maybe most?) is even writable with the right tools, and the computer's user doesn't even need to know that it's happening.
the most famous web browser that allows any website access to your USB devices with just 1 or 2 clicks makes this even worse.