In this very post you can see why: the dplyr code is just so much more readable. Like a lot of python, dplyr reads almost like pseudocode: take this dataset, select the columns that start with "bill", then filter so that bill_length is less than 30. So simple and so little fluff!
Unfortunately, having to mess around with a JVM is a tough sell for a lot of data analysis folks. I'm not saying it's rational or right, but a lot of people hear "JVM" and they go "no thank you". Personally I think it's a non-issue, but you have to meet people where they are.
I dunno, if you can slog through the Python ecosystem then the JVM is starting to look not so bad. Plus with Clojure you don't need to deal with the headache and heartache that is Maven.
Meanwhile, I find it very annoying to deal with the litany of Python versions and the distinction between global packages and user packages, and needing to manage virtual environments just to run scripts. That being said, I am not an expert but that's always been my experience when I need to do anything Python related.
idk, I don't think I've had to do anything beyond install the JVM to work with Clojure. I'm not really a fan of the clj commands flag choices though (-M, -X, etc. all make no sense)