Gnuplot is more customizable than matplotlib, more powerful, fastar and handles larger datasets, exports seamlessly to images, LaTeX, PDF, HTML5, animated gifs, among others, etc. It's a better tool than matplotlib, for me at least.

That it takes more effort to produce a "beautiful" output is myth, in my experience. People used to say that in large part because up to gnuplot 4 the default colors were ugly primary colors. On gnuplot 5 and above, it's no longer the case. Plus, you can customize the default colors/styles by editing the .gnuplot file. I've done so: https://ghostbin.com/paste/pvj5m