One of the reasons why I don't do it is because I had more than just 1 key and AMD blocks those, if you try to redeem several keys. So yeah, of course I will ask you to redeem it yourself. You could actually have known that yourself, if you had read the PDF. :-P
Or sometimes you don't receive a key for Steam, but instead you get the key unlocked directly on your Steam account. Either way, there are plenty reasons why someone should redeem those keys on their own.

I quoted the essential part from the PDF, in form of the 8 countries that can't participate. Everything else was just a service for the future winner, in case that he had any questions.
And I don't know about you, but people tend to frown if you make a give away, especially one such as for Hitman before release, and then you see someone making further demands. Even funnier: None of the people I traded with, had any complaints about that redeeming process. They paid for it and were thankful. But give it away for free and ...