The joke about R is that it is great because it was written by statisticians for statisticians and that R is terrible because it was written by statisticians for statisticians.

The two best reasons to use R, IMO, are that many statisticians write up their new methods in R, so it is a window into current statistical research and practice [0], and that R is home to ggplot and the rest of the tidyverse (or Hadley-verse), a systematic approach to common data analysis tasks.

[0] https://cran.r-project.org/web/packages/available_packages_b...

[1] https://www.tidyverse.org/