I am not a fan of using a SS water bottle as a cooking vessel or for just heating water as they are not versatile enough for my needs.
On every hike,I always carry at least one Nalgene bottle and the SS cup on the right along with my MSR Pocket Rocket Stove, matches, lighter and fuel cannister as I really enjoy a cup of tea with lunch or dinner on the trail.
If it is an overnight or multi-day hike, the Primus LITECH Trek Kettle Pot is taken. The pot holds ~32 oz and can be used to cook/warm small meals, double as a teapot and as a cup if needed. I find it much easier this way then using a SS water bottle...Ever try cleaning a SS water bottle after you attempted to cook something and it sticks to the inside of the bottle?
Either the cup or pot also works great for just boiling water for purification purposes