No, you were clear enough. I was me who was fuzzy.
I find it much easier to work on a sepia image when it's displayed in black and white. But I don't like to make the decision about whether it should be black and white until the end of the process. By using Solid Colour layers I can have a black one active while I'm working, but I can also have a brown/sepia one as the topmost layer that I can turn on and off if I want to see what it looks like in sepia.
Also, if the original image has variations of the sepia hue across the image, a brown layer evens them out.
It's not a better way, just different.