What is the point of trekking poles (instead of just poles)? I would like to have poles for my NoBo, and I already have ski poles, and don't really want to spend money on trekking poles... So why do people get trekking poles over ski poles? Aside from the weight factor, and being able to adjust the height. And I know one girl who had trekking poles with flasks in the handles (4 ounces, or something)- has anyone heard of anything like that?