Why we can't execute stored procedure in select statement in oracle? is there any strong reason?

Question

create or replace procedure pr
is
    v_date date; 
begin
    select sysdate into v_date from dual;
    DBMS_output.put_line(v_date);
end pr;

Answer 1

CREATE OR REPLACE PROCEDURE count_salas IS   V_count NUMBER(3);    
BEGIN   
SELECT COUNT(SALES.SALEQTY) as sales INTO V_count 
FROM SALES INNER JOIN EMPLOYEE ON EMPLOYEE.EMPID = SALES.EMPID WHERE EMPLOYEE.EMPID = '101';

DBMS_OUTPUT.PUT_LINE(V_count);    END  V_count;