Okay for real though... storage size? Terrible I agree.
But I've been kinda obsessed lately with the form factor of diskettes. They're:
Not super easy to lose (looking at for you, nanoSD)
They're easily labeled.
Unlike flash drives, aren't vulnerable to snagging and getting ripped out of the machine or damaging the port when inserted.
Easily stacked or filed away.
Most importantly: Make a nice satisfying "ka-chunk" when inserting into a drive.
Satisfyingly fly out of said drive when you push the eject button firmly.
Nowadays, if we made a diskette that basically replaced the magnetic disc with flash memory, and the shutter protected the connectors, you could hypothetically store like 1TB in that space, it could likely be read super fast, and would obviously be way more reliable than the old "Oh no a speck of dust ruined my 2MB file" of old floppies.
I'd even settle for an open standard akin to Sony's chunky little Memory Sticks...I liked those.
Nothing except for the limited size. I believe even today, nothing exists today for temp storage that have the convenience of diskettes.
USB Flash Drives comes close, but cheaper versions can in rare cases have firmware "virises". On a diskette, just do a format and all issues gone. Also I never even thought twice about mailing a file on a diskette expecting to never see that diskette again. Flash Drives, I still would like to get it back after mailing it out :)
No, to write to a CD, you need to use specialized software, not just a simple copy.
Plus what about copying to replaced a files already on the CD ? I believe you need to clear it first then rewrite everything back. CD are about as inconvenient as a media can get.