It may be his decision, but you know the previous 3 Manning QBs are 'consultants'. If he goes to oldpiss would that be somewhat of an endorsement of Kiffen by the consultants? They've always been pretty no nonsense people. And as an aside notwithstanding comments above - I love the Manning's as players and as a family. Archie was courageous and dedicated in a bad Saints situation. I hated when he got traded just as it was getting better.
Because he's doing it to figure out if he's wanted anywhere else; measuring the interest levels out there.