Explanation
Controlling Default Tablespace Encryption
The ENCRYPT_NEW_TABLESPACES initialization parameter controls default encryption of new tablespaces. In Database Classic Cloud Service databases, this parameter is set to CLOUD_ONLY by default. See Viewing and Modifying Initialization Parameters for additional information.
https://docs.oracle.com/en/cloud/paas/database-dbaas-cloud/csdbi/use-tablespace-encryption-this-service.html#G