Disregarding all science, the question "does weight matter if you're not racing?" is just a matter of personal preference.

I have a lightweight fixed gear commuter, a mid weight geared commuter, and a 40 pound utility cruiser. Today I sacrificed weight for snow stability and took the cruiser. Some days I sacrifice easy hill gears for simplicity and ride the fixed gear.
I commute and I ride long distance. I'm never concerned with the myriad statistics that competitive cyclists spend hours upon hours analyzing after a ride. I don't care about my weight/power ratio, or my max 30sec vs. 1min vs. 5min wattage. I care that my utility bike gets me and my groceries home from the store, and that my distance bike doesn't break down 70 miles from my house.