Because it's convenient to buy Coke.

Inside McDonald's KFC, there is basically only one drink, Coke, and when you eat things like burgers and fries, you will feel your mouth is a little dry, so you need a drink to moisten your mouth.

Although Coke is more expensive, but after all, it is these catering brand's own drinks, naturally, after taste test, not only will be more refreshing, while buying Coke just need to shout a waiter or shopping when ordering.

The phenomenon exists that you can bring your own drinks in even though Coke is more expensive in food and beverage outlets. But not everyone goes to a beverage store to buy a drink before going for a burger - after all, it's an extra trip, and buying a drink out isn't always much cheaper than a Coke.

The main thing is to go to McDonald's KFC to eat is bound to have a certain amount of spending, since there is money to buy food, how will care about this cup of Coke money? And it still feels low to bring a drink in personally.

So although the coke in these stores is expensive, the price is still reasonable compared to the food inside. The main thing is that it's more convenient to buy a Coke at these places.