Raw NAND is highly preferable to SD or USB drives. You can at least have wear leveling in the OS/FS. SD/USB are bad because most have dumb controllers and just

Raw NAND is highly preferable to SD or USB drives. You can at least have wear leveling in the OS/FS. SD/USB are bad because most have dumb controllers and just rewrite a page when it changes. Raw NAND is also consistent and meets datasheet specs, whereas SD you never know what you are getting.