It's a lot of work to tan one out, then more work to put it together properly (not nearly as hard to produce the bag as it is to tan the hide).
The bad part, in my opinion, of coyote hide possibilities bags, is that you have to add stiffeners. By the time you work down the hide and get it tanned properly, the bag will be very limp, which to me at least, is an annoying attribute for a possibilities bag. Not hard to stiffen them up, but keep that in mind as you make a pattern, or find patterns online.