Ex - lots of refs are to "multi-arch" images, Except... there's no such thing as a multi-arch image, the entire identifier is just a reference to a manifest that then points to a list of images (or other manifests) by arch, and the actual resolved artifact is a single entry in that list.
But it means the manifest needs to be able to reference and resolve other names, and that means including... names.
For a more concrete example, just check https://github.com/moby/moby/issues/44144#issuecomment-12578...
Basically - the digests weren't intended to support image verification across repos, and the tool doesn't treat them that way. The digest was intended to allow tighter specification than a tag (precisely because a publisher might push a different image to the same tag later).
The top level image hashes tend to change between repos (because the image name changes in the manifest and is included in the hash).
So you'd have to go through an verify each layer sha.
Good tool for selecting an exact image in a repo, not a replacement for trust at the naming level (it's a bit like the difference between owning a domain and cert pinning with hpkp).