This was one of the oddest professions item made available in Legion. Odd because it did nothing. Tailors would often look at it on their patterns list and scratch their heads because it served no purpose other than to use up materials better used elsewhere. At no time did Blizzard every explain why it was created.
Now, in BfA along comes the Seabreeze Saddle Blanket, which has exactly the same description on the pattern. However, here things change - this item is required by Leatherworkers in order to make the far more useful Comfortable Rider’s Barding.
So could it be assumed that the developers originally intended something similar for Legion but just never got around to creating it?
I know, not an earthsaking topic, but as someone whose first profession ever learned on a character was tailoring (and that character is still one to this day) I found it so very puzzling at the time…

