Exactly this. It checks periodically if a newer image for the tag of the container is available (e.g. vaultwarden:latest) and tells you about it. You can setup mail, sms, Teams, you name it.

So then you know a new version is available, can check the changelog and decide if the update is worth it.

Personally having great results with Diun. Same idea (check for newer container image) and works 100% for me.

Don’t know if it can automatically load and restart containers, rather do that personally.