Whether you think so or not, weight matters.
How much it matters depends on how much else you are carrying and how far/long you are carrying it.
I use to wear a duty belt that weighed about 20# which included the weight of the belt/holsters/holders for other gear, a loaded G17, 2 loaded 17 rd 9mm G17 mags, handcuffs, radio, collapsible baton, keys, respirator mask, a big can of pepper spray and a multi-tool.
FYI, one of the major causes of back problems among LEOs, resulting in permanent disability claims, is due to carrying so much weight on their duty belt.
While backpacking, I tried to limit the weight of the pack to 50# which was very hard to do, especially if I was planning long overnight treks.
Most of my packs usually ended up weighing about 70# -- at least for multi-day trips, despite my efforts to keep the weight down. I could really only do 50# on a single overnight trip.
For EDC use, when you are only carrying your keys, wallet or other such things, the weight of the knife shouldn't matter all that much but, if I can notice the "weight" in my pocket or on my belt, and I don't really "need" to carry a knife that heavy, then I won't carry it.