Realistically, it's probably not a completely even playing field. The program wants to rank enough people to match into all their slots. They're going to select the best fits to interview, and then some that would be good fits. That will stratify their rank list. Some programs put more weight on the interview than others.
But, practically, you don't know which batch you're in. You don't know how programs decide to rank people. And you don't know how far down the rank list the program will need to go to fill. So you have a non-zero chance of matching at that program once you get to the interview--whereas if you don't interview, you're extremely unlikely to match there (there could be one or two programs that rank people they don't interview, but I imagine if they exist, they are few and far between).
So, walk in to the interview with the goal of figuring out if it will be a good match for you, and sell yourself.