They provided cheap, convinient and okayish quality food, due to having resources local chains don't have.
A KFC or McDonalds in China still has to use the local farms, which means the quality isn't as bad as it might be in some American or Mexican KFC. And it will be more affordable than a lot of local restaurants that don't have the same mass contracts.
As long as they pay their taxes and follow regulations, they don't present a problem at all, so I don't see why
@Petrolicious88 thinks this is some sort of gotcha.
Local brands have advantages in cafes, teahouses, restaurants, fine dining etc, but they don't often provide the convinience or prices of big chain stores.