Good example of reductio ad absurdum argument. Of course if I chose something large enough I could show that even a 5% change is huge as a counter argument.
To claim that 0.8 pounds compared to 2.7 pounds isn’t significant is very strange to me. I carry my MacBook Air around in a messenger bag. The weight is noticeable. Nearly any amount of reduction in weight is appreciated. YMMV.
This is the thing. Apparently small differences in weight, particularly absolute for portable items but could be relative or what have you, get noticed over time. In addition to lugging around 2.02Kg of Late 2013 15" MacBook Pro (which didn't sound heavy when I bought it) I have had the opportunity to pick up and carry a number of other machines that my colleagues use.
The weight drop to 1.24Kg (780g / 39% reduction) for the M2 MacBook Air is obviously noticeable. But funnily enough, so is the difference between repeatedly manoeuvring the MacBook Air and the14" MacBook Pro that weights in at 1.6Kg (360g, 23% reduction). And the 14" Pro is noticeably lighter than my 15" Pro (420g, 21% reduction).