A vantage is a really good place from which to survey a scene. You might find that the roof of the house offers an excellent vantage from which to drop water balloons on your kid brother’s head.
Vantage is a variation of advantage, but when we use vantage we’re almost always talking about a position, not just general superiority. If you had extra tutoring for a big exam, you would have the advantage over a classmate who didn’t. But if your seat for the test allowed you to see the answer sheet lying on the desk, well then you would have a superior vantage — not that you would take advantage of that, of course!