Besides being able to achieve higher pressure (which I agree isn't terribly important), the Expeds need extra force to inflate because they're filled with down

Besides being able to achieve higher pressure (which I agree isn't terribly important), the Expeds need extra force to inflate because they're filled with down or synthetic insulation, which dramatically increases their insulating value. A R value of 1.0 isn't useful as a sleeping pad for hiking except in really warm climates. 2.5 is a realistic minimum for a three-season pad.