You're right that MOST players won't feel much of a difference of 0.2 sigma, but I certainly will .
One of my most-loathed combinations is long-reload, low sigma. When the Chonky USN BB line and IT BB lines came out, Deadeye was a thing and the accuracy took that into account. Without it, the things just felt like a Jackson Pollack painting machine. As you likely recall, Kansas especially had an atrocious sigma of 1.5 and didn't have the slot 6 accuracy module to offset it, so it was just a nightmare. Kansas has since had a buff up to 1.7 and it made all the difference in the world.