Recently, KFC Canada has accepted Bitcoin payments for a short period of time. However, Bitcoin can only be used to place orders online, and only to purchase a new item called "Bitcoin Bucket". And all this special deal will be handled by Bitpay, a fairly common Bitcoin trading tool. Its really interesting news, I wish that I can also buy chicken with Bitcoin in my coutry. 
It's a good leap forward to a cashless society, but then again, if you can pay in cash, why use bitcoins? The bitcoins you've spent on that bucket might have doubled in value in a few hours. Don't just spend your bitcoins on something that losses value over time specially food.
That is not the principle behind this. Actually, 99.9% of the time, you can pay with cash and Bitcoins are just an outspoken alternative. What this means is that adoption is slowly happening and if it goes further then that only means that the world is looking to change into a cashless society.
Also, "double in value in a few hours" is not really possible. That would mean that bitcoin prices should increase by 100% in a few hours, which has never happened in bitcoin price history.
Food doesn't lose value over time, btw. 1 bucket of KFC will not lose value in the future (unless it gets spoiled). What' you said their is actually stupid.