Yes. I had one. It died suddenly and left me with a £400 bill for a new one. Fortunately I backed up the NAS to an external disk but from this and other experiences, I've come to a general rule:

the reliability of a backup system is inversely proportional to the number of moving parts

Hence why I use beyond compare to manually sync files to two physical mediums from the master copy on my laptop. One encrypted USB stick I carry on me at all times and one hard disk that lives in a fire safe.

Moving hard disks back and forth to my fire safe is a pain. A hardened usb disk that is itself fire-rated. That I would buy.

It's hard to make anything small fire-rated, due to thermal inertia (or rather, the lack thereof).

I'm surprised I haven't seen a NAS with the hard drive enclosure fire-rated.

How about a fire-safe with a female USB port on the outside, and a male USB port on the inside - both connected? That would be cool.

Some companies sell fire-safe & waterproof HD enclosures which you can use without moving the disks.

You would need one with the mass of a fire safe which somewhat nullifies the point.