Kusanar
Loving the herd life
The jacob does felt, which is a good thing for doing spit splicing.Knotting each stitch sounds like a much slower method of construction than knitting or crochet. But once done it will stay done, that's a good thing.
I use Hula Bunny yarn for most projects since it's the yarn using the wool from our bunnies. It felts since it's an angora/Merino/silk mix and the Merino isn't superwash. Which means it doesn't come apart when anything gets a hole in it since the fibers kind of become one after awhile. I'll 'fuller' woven items which is kind of a deliberate felting and that makes it a fabric that doesn't unravel.
Does the Jacob fiber felt? Once your bag was done, it could be hand washed in hot soapy water to felt it a bit and make it even more unlikely to ever unravel.
How are you spinning the yarn if it's only in 3 to 6 foot long pieces? Or is using a short piece of yarn part of the nalbinding process?
Nalbinding uses a 3-6 foot piece of yarn on a large needle to sew in each stitch, longer yarn is more likely to tangle (especially if you overspin it... oops) and be a pain so lots of shorter lengths are used especially when starting out. There are special nalbinding needles that have 2 holes so you can put the tail of your yarn through the other hole and drag more through each time but again, it can tangle easier.
I'm hand spinning it on a drop spindle, doing about 10-15 yards at a time since I am breaking it into smaller pieces to use it anyway I can just spin for a few minutes and stop without having to worry about lost of small pieces because they will be lots of small pieces anyway.