The grammar of graphics makes a lot of sense but matplotlib was not designed with it in mind. It feels like a visualization library designed by computer scientists rather than data scientists or analysts. plotly and altair both reflect the grammar of graphics although plotly has better documentation and greater functionality.

I do enjoy the plotting capabilities of R, but Python can do some many more things besides just analysis and visualization. Plotly is enough for me at the moment, but thanks for providing several other options!