Neat, I didn't know that!
But Connor's point still stands - even with this you can't call procedures in SQL.
Using Tim's example:
EXEC get_my_results(1);
ResultSet #1
DESCRIPTION CREATED_DATE
------------------------------ --------------------
The value 1 08-DEC-2019 10:55:49
ResultSet #2
COUNT(*)
----------
3
select get_my_results(1) from dual;
select get_my_results(1) from dual
Error at Command Line : 38 Column : 8
Error report -
SQL Error: ORA-00904: "GET_MY_RESULTS": invalid identifier