One of benefit of integrating R with PowerBI is access to rich array of data visulizations not present in the standard PowerBI loadout. R is practically unlimited in the types of graphics it can create (although the amount of programming required can vary from a few lines using an existing R package, to large custom functions for truly bespoke graphics). Some of the visualizations you can create with R include population pyramids, small multiples, annotated time series, calendar heat maps, rank plots and even emoji charts. But perhaps one of the biggest opportunities is the ability to plot data on a geographic surface with choropleths, map projections, topological maps and animated maps.
If you'd like to learn how to use R maps with PowerBI, David Eldersveld from BlueGranite has put together a useful series of tutorials. In R Maps in Microsoft Power BI: Getting Started, Dave walks you through the steps of using R's maps and mapproj packages to create an interactive PowerBI dashboard to explore the (surprisingly numerous) airfields in the Great Lakes region, based on data provided by the FAA.
In part 2 of the tutorial, Dave explores using R to create small multiples: repeated maps showing data varying by time or data subset (a great way of making comparisons). This example shows the airports by type of owner (public, private, Army or Air Force):
You can learn more about how to create charts like these in PowerBI by following the link below. You can also download the PowerBI PBIX files and the modified dataset to try them out yourself.