I made a bootable backup of my M1 Air the other day using CCC and it worked absolutely fine.
The issue, as far as my quick review of all that useful documentation, is that they can’t provide all the bells and whistles of a backup that is fully under their control.
If you simply want something that you can switch to if something dies, it’s fine to use as far as I could tell and the main “problem” would be any OS updates released since you started the backup won’t be installed yet. I’m a bit hazy on that…