Layer print width settings are in mm as per manual drafting conventions. They show in the print preview and on the actual print.
There is a "PrintDisplay command that roughly approximates the the print width settings in the drawing display, but since your screen runs at a much lower resolution, it tends to be pretty pointless to try to work with PrintDisplay set to on.
It might be useful if the default hatches were loaded automatically. The first time I tried it, it worked but I had no idea WHY it worked or how it fit your instructions. When I loaded the default hatches I figured it out.
Hatch patterns, line type patterns, Layers, and other things are stored in the 3dm file. Their initial settings are inherited based on the Template file you used when your created the 3dm file.
If you chose the “No Template” option, then those additional patterns, layers, etc. are not automatically in your file.