I am aware I can buy gift cards to pay for stuff.
This isn't really living off bit coin though...I mean if I created some random currency people accepted and the only way they could cash them out was through Giftcards that were worth USD, I would say I am using USD to pay for the food.
Plus if I am in a hurry from work, or just want to stop quickly, I don't have time for that sometimes...
The point is that you are able to live off of bitcoins.
The fact that Dell uses a third party to handle bitcoin transactions makes the bitcoin purchase no less useful to bitcoin holders than if you were sending directly to a Dell bitcoin address. Same with a gift card company handling your bitcoin transaction in the physical world.