What Notes locking actually does
Lock a note and its body encrypts, openable with your device passcode or a dedicated Notes password. This is real encryption, not a display trick — the honest surprise is scope. The title stays listed. The lock is manual and per-note. And nothing about Notes prompts you when sensitive content lands in an unlocked note, which is where most of it lives in practice.
Where it strains
Three places. Visibility: a note titled "Passwords" in a shared-device household is an invitation, not a protection — locked notes are visible locked objects with visible names. Attachments: possible but clumsy, with originals lingering in Photos and no way to browse protected files as a collection. Habit: security that depends on remembering to lock each item individually degrades exactly when life gets busy.
A sane division of labour
Notes is superb at what it is for: fast, synced, searchable jottings — and the lock is genuinely useful for the occasional sensitive line in an otherwise ordinary life. The moment content is systematically private — journals, seed phrases, IDs, anything you would mind a synced device displaying — it belongs in storage that is encrypted by default, holds text, photos and files together, and does not display a padlocked list of what you protect. In Sealby, notes are markdown entries inside a vault: encrypted like everything else, organised, and invisible until the right PIN.