SSDs are faster & more stable at peak use.

Flash drives usually age poorly if pushed to the limit & will throttle your speed as it heats up.

Also M.2 standard, is well, the standard - making this portable enclosure an elite companion which you can use with interchangeable m.2 SSDs of the same form factor (there's more than one form factor for m.2).

This also means you could technically slot this drive directly into a mini PC for ex.