iCloud is overrated, it was not encrypted at rest for ages. I much prefer using Time Machine and keeping the passcodes in a PW manager, and maybe a safe deposit box as a backup.
iCloud is a whole lot of things. What you describe is a backup storage solution.
Time Machine does not handle:
- photo sync between devices and users
- shared storage between devices and users (no, not backup, but actual directories and files etc)
- private relay
- state sync for games and other apps
- etc etc