If I had your device there's no way I'm getting any information out of it without your passcode or finger. Sure there are tools out there to hack into the device, but not available to the average dirtbag. Without your passcode or fingerprint, no one's getting in. However, your computer may or may not have the same level of access restriction, hence the option to encrypt the computer's copy of your backup.
"However, your computer may or may not have the same level of access restriction" - If you elaborated on this it might lead somewhere.
I thought I had and I wish I had the option to encrypt the computer's copy of the backup. That's what I thought I turned on. However, this option apparently also locks out my ability to create unencrypted backups in the future. The option does more than one thing, and it doesn't tell me that it is doing the 2nd thing, and it permanently locks me out without giving me any warning.
Apple doesn't need to mention anything because it is quite evident that applying encryption requires you to remember the password (hence the requirement to verify the password you chose when you set it).
I agree that it is quite evident that applying encryption requires me to remember the password, in order to decrypt whatever I encrypted. In this case, I was encrypting a local backup on my computer. I forgot the password and I fully accept that I cannot decrypt the backup (if I still had it).
You seem to be confused ... encrypting your backup does not make your device inaccessible or locked out for normal use.
I am fully aware that I have not been locked out for normal daily use, as I have been using the device daily for years. I would think that making unencrypted backups is also normal use, and I should not be denied that normal use simply because once upon a time I encrypted a backup on some computer that I might not have anymore.
Your computer analogy does not apply to this scenario at all ... name a situation "in the normal computer world" where if you password-protect some information that you still have the ability to access the same (protected) information without the password. In some computer situations there are password recovery options, but not in situations where you, the user, assign and administer the password yourself.
This isn't that complicated. If I have a server and I create a backup of the server on my local computer, and I encrypt that backup with a password, then my server is not encrypted; only the backup on my local computer is encrypted. Of course I can't access the backup without the password. However, my backup software would not encrypt (or cripple) my server without asking me to. That would be insane.