For my Epson P600, on a Mac, under Media Type (= Medium on your screen shot), there is an option 'Fine Art Paper', which then has several sub-options, including 'Watercolor Paper - Radiant White'.
On my computer, at the moment, that option, and others e.g. Velvet Fine Art Paper, are greyed out, i.e. not selectable. I suspect that this has something to do with legacy support, and where the (paper) profiles are stored. On my computer, the paper profiles for my printer are stored at
Macintosh HD/Library/ColorSync/Profiles/Epson SC-P600, e.g. EPSON_P600_Exhibition_Fiber_Paper_PK_v3.icm. As far as I recall, at some point after getting the P600, I went to the Epson web site and downloaded profiles, perhaps as a zipped bundle, or two. I also have a couple of Hahnemühle profiles (.icc's) there. When I got the P600 Epson profiles, there weren't any for Velvet Fine Art (or Watercolor Radiant White). They were mostly for more 'special' papers such as the Exhibition Fiber. My guess would be that the media options presented are a combination of hard-coded standard(?) papers and more special papers for which the printer driver has found specific (Epson)profiles, but that some of the (old?) standards are not actually supported for the P600. I will confess that this is an aspect of printing that I find somewhat confusing, so I may be completely wrong, e.g. I don't the difference between a .icc and a .icm profile file. My experience is with Epson printers.
