If it's designed for climbing, I take that as meaning that the extra weight is probably going into durability. That is probably an acceptable trade off for me, as most of these insulated jackets that I have seen seem pretty flimsy to me and don't seem like they'd last all that long for how I use them (brushing up against rocks/foliage, resting on rough mountain rocks, getting snagged on various things from time-to-time). Maybe I'm underestimating the durability of most of these jackets.