Having tried to keep "permanent" backups of my personal digital data for 35+ years, I should point out that one should not underestimate the problem of technological change.

The "device" you use today will, in all probability, not be usable after a number of years, no matter whether you spin it up regularly and maintain it in a working condition.

I have backups in countless floppies, diskettes, Zip drives, 9-track, QIC, DAT, SCSI, ...