Microsoft gift cards for Windows Phone Store

Are these region dependent? Meaning do I have to be physically be in the supported country for this to work? I'm looking to purchase a Lumia 1020 in the next few days. I reside in Pakistan and the regional store here is quite lacking. I usually set the phone region to US and browse that store for all the apps.

And since I obviously don't have a US credit card, my only choice is a MS gift card. I can ask someone to buy it for me and send me the code. All I need to do is enter it into the wallet and it will work and let me download stuff?

Is this the gift card?

http://www.microsoft.com/en-us/account/giftcard/default.aspx