One story is more family friendly and accessible than a two-story. Family members, especially with laptops tend to retreat upstairs for privacy. Then again a two-story is better for those who need more privacy and separation from public areas.
One story requires less of everything--furniture, cleaning supplies, vacuum cleaners. Laundry is closer to bedroom in most cases so no hauling laundry up and down. Cleaning in general is more efficient.
In a one-story, people can hear each other, join in for a second, stick their heads in the living areas from their bedrooms in a one-story, go back to bedroom without going up and down stairs.
Outdoors, if there are nice yards, are more of an extension of a one-story home.
Q