It's not always about the weight, for the last time. There are as many reasons to use a hammock anywhere, anytime, as there are people. Convenient? I find it a whole lot more convenient to keep all my gear OFF THE GROUND. I can set up in the rain, sleep, take down in the rain, and never get the contents of my pack wet. I also don't track leaves and mud in, nor do I have to get out from under the tarp to put on rain gear.

My hammock setup is lighter than the tent/pad/bag combos of my hiking companions. I am the closest thing to an ultralighter in my hiking group, and I don't claim to be ultra, just lightweight. I'm comfortable in temps down to 25F and it all goes in 4000 cu in. That suits me fine.