To be honest, pounds mostly likely don't matter but that doesn't mean pounds are insignificant. The problem with thinking something is insignificant is you keep adding them to your pack until real weight differences are added. Commitment to lightweight backpacking is thinking about everything you put on your back and really deciding if this is something you want to drag down the trail. Many people, myself included, have a problem with there gear creeping up in weight over time. You then find yourself half way up a mountain swearing you won't bring so much crap next time.

The guys who drill holes in there toothbrush handle will certainly never be able to tell the effect on their pack weight, but it shows (an obsessive) commitment to reducing pack weight. If you don't have at least a little of that obsessiveness, you quickly find yourself with an oppressively heavy pack.