"3) A clutter free space tends to be cleaner, and the lack of visual clutter relieves stress. "stuff" tends to get sorted, moved, and scattered. It collects dust. Consider the diffence between a table stacked with items and a table with a single lovely vase on it."
It is subjective, a difference in aesthetics. The table with a single lovely vase looks like a hotel room or hospital to me. Our coffee table, which currently holds about a dozen books representing all family members, a pair of binoculars, a flashlight, and a much-abused Christmas cactus, feels comfortably lived-in. I've often read that "lack of visual clutter relieves stress," but I think it's an unfounded claim that's acquired common-wisdom status. I could as easily say that the rich texture and variety of cluttered space stimulates the mind, warms the space, and offers opportunity for serendipity.
I do understand the folks who say we are paying to heat and store belongings, but as KGZ said, other circumstances keep us (for now) in a house 10-20% larger than we need. But even when we lived in smaller places, this was our way. Where we live, houses without cellars are rare. I grew up in a 900 sq.ft. house with a (cluttered) 900 sq.ft. basement and attic.
Today I am going to a baby shower. I am giving the new mother my children's old-but-very-clean crib and playpen, which I have stored 6 years since my youngest used it. It should save her a few hundred dollars, prevent the pollution of newly manufactured ones, and keep the old ones out of the landfill.