Cheaper, sturdier, and more easily swappable than NVME while still being far faster than spinning discs. I use them basically as independent cartridges, this one's work, that one's a couple TB of raw video files plus the associated editor project, that one has games and movies. I can confidently travel with 3-4 unprotected in my bag.

There's probably a similar cost usb-c solution these days, and I use a usb adapter if I'm not at my desktop, but in general I like the format.