I honestly think it goes both ways.

It'll cause more people to be interested in bitcoin since it's now showing to be a viable currency to use in everyday situations, like buying food, and if KFC deems it a successful strategy to accept it, it may open up more companies to jump on board to accepting btc. Which in the long run helps the holder of the crypto (most likely a majority of the people on this board).

However, on the other hand, it could simply be a gimmick which can be a possibility.