As far as I see I wouldn’t trust a floppy disk to carry info across a room let alone to use as storage for a long period of time. They are too sensitive to environmental issues and static electricity. I found this info:
The MTBF for Floppy Disks is typically 30,000h whereby USB Flash Drives typically have a MTBF of 300,000h, which is mainly limited by the insertion cycles. The operating temperature range for Floppy Disk Drives is typically in the range of 5’C to 52’C whereby typically USB Flash Drives operate over a temperature range of 0’C to 70’C
There is a lot more information in the original article: USB Flash Drive White Paper.
Tape is still the standard option for long term storage of data. This is because of the large amount of data you can get on a single tape (800GB per tape compressed isn’t unheard of). However to store tape for long periods of time you have to keep them in a cool dry room.
I wouldn’t want to keep a lot of data on USB thumb drives for long periods of time as remembering what’s on which thumb drive will be a pain.