Ubuntu:focal VS ubuntu:latest

$ docker inspect ubuntu:focal | grep ubuntu
            "ubuntu:focal"
            "ubuntu@sha256:0b897358ff6624825fb50d20ffb605ab0eaea77ced0adb8c6a4b756513dec6fc"
                "org.opencontainers.image.ref.name": "ubuntu",

$ docker inspect ubuntu | grep ubuntu
            "ubuntu:latest"
            "ubuntu@sha256:20fa2d7bb4de7723f542be5923b06c4d704370f0390e4ae9e1c833c8785644c1"

Differences (general overview)?
Differences (concrete differences)?
Differences (show concrete differences with practical examples)?
When to choose one version rather than the other?
Why choose one version rather than the other?