Oracle auditing: Is it possible to log when a permission is being used?
Yes, that is entirely possible. The use of any privilege or grant can be audited by instance, by session, by success, or by failure. You can audit all uses, or just uses by specific users. See here for a basic guide to getting started: https://oracle-base.com/articles/8i/auditing, and here: https://oracle-base.com/articles/12c/auditing-enhancements-12cr1
For example:

CREATE AUDIT POLICY test_audit_policy
  PRIVILEGES CREATE TABLE, CREATE SEQUENCE
  WHEN    'SYS_CONTEXT(''USERENV'', ''SESSION_USER'') = ''TEST'''
  EVALUATE PER SESSION
  CONTAINER = CURRENT;

AUDIT POLICY test_audit_policy;


See here for a blog I wrote a few weeks ago about basic audits to use in 12c and up, called &quot;Auditing By The Numbers&quot;