Wonderful demonstration. I can't help but wonder--as someone who has flirted with R but certainly not committed--how much time and practice it takes to acquire decent fluency with these half-magical incantations to become productive.
The main thing is that ggplot2 has been around for a long time, is developed by people that care a lot about R, and there is pretty much an answer to any question you may have on stackoverflow.
The syntax being shown here demonstrates an incremental way of layering on the components of the final visualization, which shows the power of the underlying grammar of graphics.