The difference between OIDC and OAuth boils down to exchanging attribute assertions describing a user as opposed to the delegation of a specific set of allowed actions, as OAuth was intended to do. OIDC and SAML are basically the same thing, with OIDC being a somewhat less frightening and more modern protocol.
Reading the user's profile information _is_ the delegated action. OAuth providers were already doing this prior to OIDC but in incompatible ways. OIDC standardized how that information is requested and returned.
