Not everyone lives in the country.
Those in California can tell you the movement, as can anyone in a metropolitan area who has large trucks, airplanes, helicopters, etc... that cause vibrations.
That blade bouncing up and down on a surface, combined with the natural wood movement under it, wears down a blade. So you can sharpen it up, set it aside, and come back and go to make a swipe and ruin the piece the you are working on due to a worn blade or burr.
To each their own- as I said before, the average DIY'er and Contractor won't care, as this place is filled with them. But head over to a wood forum or to any of the big names that have their own schools, and will get laughed out. My planes range in value form a few buck to several hundreds of dollars. The blades will laws forever if cared for, and I care for mine well.