A scatter plot definitely shows more information than a pair of histograms. Who knows if that additional information will be useful.
It would be nice if the article actually compared different visualizations of the same data, rather than showing histograms of 2 separate data sets and scatter plots of a 3rd data set.
Though a scatterplot conveys less information (e.g. the correlations between the two axes), I think it takes longer to process. It also takes more screen real estate than a pair of histograms.
