The best comparison I can make for the channels generated by the YRGBK script is to look at the color set as a kind of color mode, or color model. Like CMYK, the colors can be printed if you have decent control over the variables. With a few adjustments the color channels can be used to create custom color separations. Looking at YRGBK as a color Mode, which can be printed or used to create custom separations, helps to understand its capabilities and limitations
In this video I am using the script to begin a custom color separation in Adobe Photoshop® CC. I check the Custom black, Gray and the Color Settings options. This generates a gray channel and displays the Black options and the Color Settings preferences.
The color settings handles both the dot gain preview for spot colors, and the dot gain adjustment used in the color conversion. The dot gain for this print is almost 40%, so I am using the Custom Dot Gain option.
At the end you can see the results of the script. The image used is from the original Photoshop document at 300 ppi, which shows in the quality of the channels.