[TACD]

MiniDisc would have been an ideal successor to the floppy disk if only Sony had unclenched their fist just a little bit. USB sticks are higher capacity but there's utility in having media you don't have to keep track of; especially in the early 2000s it would have been very handy to give somebody a MiniDisc of data and just say "don't worry too much about getting that back to me, I have a whole box at home".

We had rewriteable CDs but they were so awkward, large, and unreliable that it never quite filled that need.

[Melatonic]

Yeah - like many things Sony they went to proprietary and locked down

[rbanffy]

True. They screwed themselves thoroughly multiple times.

[SpecialistK]

It could have beaten the Zip Disk and helped MD be adopted as a music format ("oh I have a few of these already, might as well get [a Walkman / PC drive]")