I would think that the deciding factors for carrying hemostatic gauze usually aren’t space and weight — you’ll likely be carrying some kind of gauze anyway. For me it’s cost. A good hemostatic gauze is one of the most expensive components of a single-person trauma aid kit, and unlike the other most expensive components (a CoTCCC recommended tourniquet and often the pouch the kit is carried in) they need to be replaced every few years.