Why not? Most of the people nowadays knows McDonalds , and it is very essential for bitcoin to be introduced in different country but the thing is are the people surrwounds were willing to accept it as way payment? As soon as possible? I think it will happened but not in 2018
It is possible to happen in the near future because of its potentials. But I think the transaction might gets so complicated. Imagine, you will going to pay a bitcoin for a certain meal then suddenly you will notice that the payment transaction is pending. I think bitcoin won't work that easy in paying for Mc Donalds meals by 2018. Many studies and testing has to be done before it work efficiently.