Sometimes users are trying to perform certain operations (e.g., promoting/moving artifacts using REST API) only to find themselves running into a permissions error, such as:
User doesn't have permissions to override '<Repo-name>/<folder>/'. Needs delete permissions.
This can occur when a given user has, for example, permissions only up to deploy/cache (which are insufficient to execute the operation above), but not delete/overwrite.
Without delete/overwrite permissions, a move operation will not be supported because that action implies the deletion of an artifact from one location and its deployment to another. However, one can still use the copy option, as that only requires deploy/cache permissions.