In my opinion, I think it is Carl's choice wether he wants to buy the game or rent it. And I think that the reasons for him to do so are HIS reasons and HIS opinions. Wether you people agree with his reasons for buying or renting the game does not matter because, after all, those are YOUR reasons/opinions and the only reasons that DO matter in the end are his, because it is his choice and he is the one who decides what to do and why he does it :P
Or at least that's what I think =P