how should I check effect of using ‘return as locator’ if its possible to track changes through column size after data insert?

Refer to object-relational-developers-guide/Nested Table Locators
‘For large child sets, the parent row and a locator to the child set can be returned so that the child rows can be accessed on demand; the child sets also can be filtered. Using nested table locators enables you to avoid unnecessarily transporting child rows for every parent.’ I couldn’t find any difference in size column by using ‘return as locator’ , would you please see my examples as follows and let me know how should I check effect of using ‘return as locator’ if its possible to track changes through column size after data insert or some thing like that? thank you.

create type inner_table as table of number;
/

create type middle_table as table of inner_table;
/

create type outer_table as table of middle_table;
/

create table tab1
(
    col1    number,
    col2    outer_table
)
nested table col2
    store as col2_ntab (
        nested table column_value
            store as cval1_ntab (
                nested table column_value
                    store as cval2_ntab
                    return as locator));
/



insert into tab1
     values (2,
             outer_table (middle_table (inner_table (1,
                                                     2,
                                                     3,
                                                     4,
                                                     5),
                                        inner_table (10,
                                                     20,
                                                     30,
                                                     40,
                                                     50)),
                          middle_table (inner_table (1000,
                                                     2000,
                                                     3000,
                                                     4000,
                                                     5000),
                                        inner_table (10000,
                                                     20000,
                                                     30000,
                                                     40000,
                                                     50000))))
/

select /*+ NESTED_TABLE_GET_REFS +*/
       col1,
       col2,
       t1.*,
       t2.*,
       t3.*
  from tab1                     t0,
       table (t0.col2)          t1,
       table (t1.column_value)  t2,
       table (t2.column_value)  t3
/