An MVP by definition is the very base point that you can convince people to buy your wares. Whatever form that takes will depend on you and your market. The point is to get whatever you have up there in your head and put it out into the world; who cares what that looks like. Landing pages are so popular because it's the path of least resistance in getting your idea in front of a sizable audience. Going straight to a working prototype for your MVP without hitting the landing page or comparable stage first sort of misses the mark on what an MVP is all about.

Instead of thinking of an MVP as a single _thing_, we just made things easy and called everything we did our "MVP" until we started doing recurring sales.