Private by default
A journal is only useful if you are honest in it, and you are only honest if you trust where it lives. Look for per-entry privacy — a place to file things nobody else ever reaches, separate from anything you choose to share.
In KNOW ME - SHOW ME that split is built into the vault: PUBLIC, PRIVATE, PROJECT, and ADVISOR sub-vaults, each with its own colour and its own rules.
Grounded, not invented
The failure mode of AI journaling tools is confident invention: a quote that was never said, a study that does not exist, a painting with a made-up meaning. Insist on citations, and insist that the tool refuses when it has nothing real to draw on.
Every answer here names its source and shows how strongly it applies to the entry you asked about.
Ownership and export
You should be able to walk out with everything: full vault export to Word and PDF, printable keepsakes, and a clear account-deletion path.