Interesting articles...but they still seem to support that nitrogen is better. The first article does say moist air expands more than straight nitrogen, and the second seems to have run tests using very dry desert air in the comparison. Less loss of pressure through the rubber, less corrosion, more consistent expansion. I'm still liking my dealership!
All almost completely useless on a street driven vehicle owned by someone who checks tire pressure at least once every month.
And the moisture thing is BS. The nitrogen might be dry, but the soapy water that the tech sloshes onto the rim/tire to make the bead seat easier is still going to be in there after most of the air is sucked out, and the nitrogen pumped in.
Corrosion usually forms on the outer edge of the bead, nor from the inside out. All you can do to slow that process is to keep the rims clean.
If the dealership/shop fills with nitrogen exclusively, great, no harm done. If they charge extra, save your money.