R is good for one-off analysis problems, but is really bad for large distributed production systems. My team moved a large internal analysis application from R to Python because Python works well for both statisticians and software engineers.

I know R and have used it in the past. I just don’t like the language. I keep RStudio around though because on rare occasions I do look around in it to see if it has something I need. So rarely though that I forgot to list it...

I think it is safe to say that they don't think it's too important for them given their main message, but hey, maybe they have an opinion anyway...

If you have Mathematica, you might not need R as both are like Swiss Army Chainsaws for Data Analytics.