The manual says https://wiki.mikrotik.com/wiki/Manual:System/Backup
dont-encrypt (yes | no; Default: no) Disable backup file encryption. Note that since RouterOS v6.43 without a provided password the backup file is unencrypted.
however the Winbox user interface doesn’t default to ticking the box “dont-encrypt” leading to a false presumption of being encrypted as the box is not ticket. As a side product ticking the box does nothing, literally meaning the tickbox has no function what so ever.
You already write it: it does not encrypt if the password is not set…
If anyone thinks it’s encrypted, they think wrong.
They think wrong because the tickbox is not ticked (by default) and the tickbox says it is encrypted if not ticked… nowhere in the interface is it mentioned it would not be encrypted if the tickbox is not ticked. Especially as it before 6.43 defaulted to encrypting the backup with the user password by default, with the same tickbox (by default) not ticked.
rextended maybe you really should relax a bit and forgo the useless comments to all posts, even though much of your insight is harsh but spot on. You feedback is not helping to produce a logical and reasonable user interface, which is supposed to guide towards predictable actions.