Should important files in iCloud also be backed up elsewhere?
The new paradigm is…
&quot;Any data which is stored in fewer than three distinct locations ought to be considered temporary.&quot;
Late Edit:
Don't use a sync solution as a backup.
iCloud is not primarily a backup solution, it is a sync solution. It will come back to bite you hard if you accidentally delete a file from one device… the helpful sync service will then dutifully delete it from every device.
For 'distinct locations', personally, I use 4, in degrees of 'distance'.

My Mac, which has not only my Mac data but also my iDevice backups.
Time Machine, containing all of 1.

1 &amp; 2 are both in the same building, so if the house burns down, I need another location, off-site.

iCloud, containing only a subset of 1 &amp; 2 [primarily iPhone backups, just because they happen automatically] which is not enough to recover everything in case of disaster.

Backblaze [other offsite backup structures are available] which has copies of everything in 1, 2, &amp; 3 above.


I also have my boot drive cloned, for rapid recovery in case of drive failure, but that is also in the house, so classes as part of 1 &amp; 2.
I consider iCloud to contain my keychain in case of catastrophe. I don't consider it as any kind of 'storage', per se. I don't trust it with my photos or my music, for instance, I have all that data stored in 1, the Mac. I consider my Mac to be the primary location for all my data. It has 13TB of storage &amp; nearly 20 years of unbroken historical data.