Sample size of 1, but I ran an RPi4 just fine on a USB thumb drive for about a year. Still upgraded to an SSD later because I wanted even more storage space (a

Sample size of 1, but I ran an RPi4 just fine on a USB thumb drive for about a year. Still upgraded to an SSD later because I wanted even more storage space (and SSD seemed to have better random IOPS than a thumb-drive), but I'd say go for it.