Several reasons actually. I'm still a bit of a novice, it only has 28" of working limb on each half and I couldn't find a definitive answer on the physics of working limb length vs total length and my draw length is long, I was able to get a good amount of reflex, and most importantly I love working with sinew.
I should probably get checked out. I can spend a whole afternoon putting on one strand at a time and just be in my happy place. Heck, I've even sinewed on wood tool handles like rasps and files, works great for keeping the two together. I enjoy the whole process from pounding and pulling to making hide glue. I think it's in my DNA. Any excuse to play with sinew is good day.