missing data in information_schema grant_* tables?

Hello pgdevs,

I'm trying to use the information_schema, and I'm looking at the grant
tables. ISTM that some views do not show all expected permissions.
 psql> CREATE TABLE foo(); psql> CREATE USER calvin NOLOGIN; psql> GRANT SELECT ON TABLE foo TO calvin; psql> GRANT
INSERTON TABLE foo TO PUBLIC; -- not really a good idea
 
 psql> \dp                            Access privileges Schema | Name | Type  |   Access privileges   | Column access
privileges
--------+------+-------+-----------------------+-------------------------- public | foo  | table |
fabien=arwdDxt/fabien|                       : calvin=r/fabien                       : =a/fabien
 

INSERT to PUBLIC is shown on the last line of the access privileges 
column. However, when looking at the information_schema:
 psql> SELECT grantor, grantee, privilege_type       FROM information_schema.role_table_grants       WHERE table_name =
'foo';grantor | grantee | privilege_type
 
---------+---------+---------------- fabien  | fabien  | SELECT fabien  | fabien  | INSERT fabien  | fabien  | UPDATE
fabien | fabien  | DELETE fabien  | fabien  | TRUNCATE fabien  | fabien  | REFERENCES fabien  | fabien  | TRIGGER
fabien | calvin  | SELECT
 
(8 rows)

My point is that the grant to "PUBLIC" does not show in the information 
schema. However, it appears in the table_privileges view:
 psql> SELECT grantor, grantee, privilege_type FROM 
information_schema.table_privileges WHERE table_name='foo'; grantor | grantee | privilege_type
---------+---------+---------------- ... same as previous query ... fabien  | PUBLIC  | INSERT

(1) Would you agree that it is a "bug"? That is, if the grantee is PUBLIC, 
it is an enabled role for the current user, so it should appear in the 
role_table_grants view...

(2) If yes is the answer to the previous question, and in order to fix it, 
would it be acceptable to drop the view definitions of role_table_grants 
based on the pg_catalog and rely on the table_privileges view instead, if 
possible (it looks so, but there may be some issues)? Or should the 
current view definition be simply reworked?

-- 
Fabien.