There is, as one might expect, quite a long history of such tools, since text-only interfaces were the norm in the olden days.

When I was a young one doing physics in the '80s, we used CERN's HBOOK[1] to do all our (statistical) plotting. Recently while working on a Common Lisp project I had a use for something similar, remembered HBOOK, and "rolled my own"[2] (much simpler version).

Yes, a nice clean graph in a GUI or PDF is cleaner, but if you're working at the terminal already or in a REPL, it can be nice to just see the output there.

At the risk of downvotes: I do wish this particular project didn't require a working Ruby / Gem installation -- nothing against Ruby, but I'd be curious if there was an equivalent stand-alone executable written in Go or similar... something like [3]?

[1] https://cds.cern.ch/record/307945/files/ [2] https://github.com/eigenhombre/hbook [3] https://github.com/gizak/termui