Seems awfully heavy for what it does. Still, an interesting gadget.
Smaller sizes weigh about a pound or so. What does your water filter, UV pen, stove, fuel and fuel bottle, water bottle and cooking pot weigh?
The lightest weight for a kelly kettle in the cited sources was 1lb, 13 oz. If I were going lightweight, the alternative I would choose is an sub liter aluminum pot (or recycled coffee can, if we are saving money, weighing , oh, say, 4 oz. Now life is simplified and there is no need for water filter, UV pen, stove, fuel,or fuel bottle. Build a fire, boil water, brew tea, and enjoy life.
When I started in the outdoors, we routinely cooked on campfires. Later I went to various stoves for convenience and use above timberline and during winter climbing trips. On most of my normal trips, either on foot or by bike, I now favor a gas canister stove, but I retain the ability to build a simple campfire using available fuel. In an emergency situation, the campfire cooks your food, purifies your water, and directly heats your body and the immediate surroundings, as well as signaling your location.
The Kelly kettle would definitely be a good tool if you are in stealth mode.