FLASHBACK privilege causes ORA-01720 - is this OK?

I understand that ORA-01720 is shown when non-SELECT grant is applied to a read only view (e.g. DUAL).

However FLASHBACK privilege seems to me like read-only.

But the following GRANT fails with "ORA-01720: grant option does not exist for 'SYS.DUAL'"

CREATE OR REPLACE VIEW TEST_VIEW AS SELECT TO_CHAR(SYSDATE,'HH24:MI') AS VALUE_TEXT FROM dual;

GRANT FLASHBACK ON TEST_VIEW  TO PUBLIC;

Don't you think this is not right and FLASHBACK should be allowed?