Earlier quoted context omitted.
For a long time, if you used full disk encryption, the encryption key never left your machine. If you forgot your password, the data was gone - tough luck, should have made a backup. That's still how it works on Linux. Pretty surprising they'd back up the disk encryption secrets to the cloud at all, IMHO, let alone that they'd back it up in plaintext.
Well, for a consumer notebook or mobile device, the threat model typically envisions a thief grabbing it from a coffeehouse or hotel room. So your key needs to be safeguarded from the opportunist who possesses your hardware illegally. Linux can be fairly well-secured against state-level threat actors, but honestly, if your adversary is your own nation-state, then no amount of security is going to protect you! For Mic…
But One-drive is essentially a mass-surveillance tool. It's a way to load the contents of every single person's computer into Palentir or similar tools and, say, for instance, "give me a list of everyone who harbors anti-ICE sentiments."
By the way my windows computer nags me incessantly about "setting up backups" with no obvious way to turn off the nags, only a "remind me later" button. I assume at some point the option to not have backups will go away.