This would be a great benefit. I think 20 or 30 years down the line we'll start to see a lot more architectural mega projects like the Kingdom Tower in Saudi Arabia, and I think an emerging feature you'll start to see is huge communal green areas halfway up and at the top of the towers. Finally, residents of flats, apartments and penthouses might be able to get some real garden space.
On a smaller scale, if I were limited to a small plot of land I'd rather have a bungalow with a garden on the roof and easy access than a two-story house with no garden - any day of the week.