It feeds the green eyed monster that occupy the souls of Cassius and Brutus. They will interpret it not as triumph, but as ambition. They despise his need to show ambition. That's their interpretation: it is not that of either Caesar or Mark Anthony.
We are waiting for the ambition to show itself. And they are waiting to exchange words on it. We wait right along with them. That in itself creates tension and suspense. As the plot develops, we see how this all is building.
