What does it mean that Microsoft Teams Tab apps must provide value beyond hosting an existing websit

In the "Teams Store validation guidelines" article, it says "https://learn.microsoft.com/en-us/microsoftteams/platform/concepts/deploy-and-publish/appsource/prepare/teams-store-validation-guidelines#:~:text=Tabs%20must%20provide%20value%20beyond%20hosting%20an%20existing%20website.%20%5BMandatory%20Fix%5DMandatory Fixhttps://learn.microsoft.com/en-us/microsoftteams/platform/concepts/deploy-and-publish/appsource/prepare/teams-store-validation-guidelines#:~:text=Tabs%20must%20provide%20value%20beyond%20hosting%20an%20existing%20website.%20%5BMandatory%20Fix%5D". What does it mean for a tab to provide value beyond hosting an existing website? Does that mean it also has to have a message extension or bot aspect to it?