I think you are incorrect. I've looked into my Keychain Access > iCloud on Mac and found some entries that seemlike they were created with the APIs you suggest.
E.g. WizzAir has three entries: `WizzAirLogin.username`, `WizzAirLogin.password` an `WizzAirLogin.firstName`.
Or Spotify stored `com.spotify.login.credentials`, `com.spotify.connect.lastStoredDataKey` and `com.spotify.connect.iplSessionHistoryDataKey`.
E.g. WizzAir has three entries: `WizzAirLogin.username`, `WizzAirLogin.password` an `WizzAirLogin.firstName`.
Or Spotify stored `com.spotify.login.credentials`, `com.spotify.connect.lastStoredDataKey` and `com.spotify.connect.iplSessionHistoryDataKey`.