Give us 1 reason why you need a full strength haul loop???

I really don't know what you mean here. Again, the tech behind the arc'teryx harnesses prevents this from being practical. Harnesses achieve comfort by spreading the load across a wider area. More traditional harnesses use a strip of webbing as the structural component, and spread the load via padding. The arc'teryx harnesses work very differently. They essentially take a strip of webbing, remove the vertical fibers in parts of it, and then spread the horizontal fibers out forming a waist belt shape. This is then laminated to hold its shape. The entire waist band is structural webbing. There is no padding because the load is already spread pretty well across the harness. The only way to make a belay loop-like attachment would be to spread out the webbing twice, with a second point of convergence dead center in the back. This would be horribly uncomfortable, expensive, and virtually impossible to size correctly. In my opinion, full strength haul loops aren't all that useful anyway. It mostly just ends up holding my chalk bag.