I'll respectfully disagree with you and will even go on the record and say that I'm likely in better shape than most folks who don't do paper work.
A few ounces may not matter, but when you get to a 2 lb difference (saw, bar + chain), if you are doing a lot of limbing with the saw all day long, very few people will not notice the difference at the end of the day, and that includes a lot of pros, especially those who do a lot of reaching from buckets, etc.
One of my Tree guys has tendonitis from all the work he does, and if you don't think he pays a great deal of attention to the weight of his saws now, you are wrong.
I will freely acknowledge that the older you get, the more difference it makes, when you are young and strong you can get away with a lot (I'll tell you that few people could keep pace with me when I was in my 20s and worked for the moving company). You won't find many more physically demanding jobs than that, a lot of long days, and carrying pianos and organs up and down flights of stairs.
If you are mostly bucking on a landing, the saw weight does not much matter. But like I said, it depends on what type of work you do, and how old you are.