I wrote an article about this for my employer[0]. There's also a nice list of use cases in the RFC[1], including (text in parens mine):

* Migration of the Identities

* Single Sign-On (SSO) Service (allowing provisioning instead of JIT)

* Provisioning of the User Accounts for a Community of Interest (with complex infra)

* Transfer of Attributes to a Relying Party's Website (so profile data)

* Change Notification (of profile data and access)

0: https://fusionauth.io/articles/identity-basics/what-is-scim

1: https://datatracker.ietf.org/doc/html/rfc7642#section-3