at least being on a thumb drive would be more durable, compact, and have faster read time.

Actualy, thumb drive flash is the lowest quality, cheapest one (the yield thing, the outer parts of the waver). Do not expect your data to keep longer than a few hours weeks.

Edit:

Because that's how yields work, defective areas get firmware-disabled in the factory. Lower quality has only more of them, with less strict quality requirements to count as ok.

To add, it's a gamble; most are ok, some get data corruption on write, some after weeks. The "cheap" part is, because they aren't expected to last more than a few TBW.