It's a little hard to visualize what total amount of stuff you're planning to deliver to the library, but it appears that you may be talking about a fairly large number of devices for SD &/or Memory Sticks.

A disadvantage of the small size is the difficulty of affixing physical labels so that users can find the one wanted. Sorting through even a small bunch of individual devices to find the ones wanted can mean a significant amount of handling for all of them, unless you've got numbered slots to put them in, in a cabinet or file box. A "proper storage" at least partly negates the small individual size.

SD cards generally require inserting the cards into a reader of some kind, and while they're fine while they live in a phone or camera, when you have to pull them out and stuff them in somewhere else, there's some risk of mechanical damage. Many memory sticks have retractable connectors and/or covers. The retractables are more durable due to breakage of some kinds of the covers, but not all of them "lock extended" securely, with the result that they get abused by people trying to get them in the socket. Careful selection of a single specific kind of stick can help some.

SD & memory sticks in my local retail market seem to "sweet spot" at about 20 GB, beyond which the price per bit goes up by a fair amount as capacity increases. A TB of 20GB devices is 50 parts to label and keep track of, and at the retail $28/device a TB of storage runs up to $1400. I haven't looked for quantity prices, but that seems rather steep when you can get a portable USB 1TB hard drive for about $120 at single unit retail.

With 50 devices, you'll probably want at least one "index device" to keep track of what one to pull out when you want a particular data track.

A single 1TB portable HD can use the same USB connection as the thumb drives, and can have an index file up front on the same device.

I haven't seen portable HDs larger than 1TB easily available, and although the "desktop USB external HDs" run up to 5 TB fairly economically, the desktop units I've used have failed miserably when moved around and otherwise handled, even with meticulous care to be sure they're never moved while running and with careful shock protection in transit. (3 of 5 failed in one or two trips each, when used while parked out on the road.)

Using Western Digital and Seagate Portable External USB Drives, with 3 1TB, 4 500GB, and a couple of 300 GB drives, some around 6 years old, I've yet to see a failure (still being careful with handling). Both of these makers have USB-3 units available now, with 1 TB at a little over $100 each. I don't have a USB-3 port as yet, and at USB-2 it takes a few hours to copy a half-T, but retrieving individual files is about as fast as for the internal HDs I have. USB-3 will eventually be available and claims 10x speed over USB-2, so it's probably worth looking for the faster drives so that you'll have the better speed when the computers catch up. (Note that this isn't a particular recommendaton for the makers I've named. That's just what's handy in my local markets.)

This isn't meant to argue with what you've planned - but bunches of little parts being handled by people you don't get to train carefully always made me nervous when I had to be "responsible" for results. Now that I'm fully retired and irresponsible, the final decisions are up to others - like you.

John