One of the main reasons why real estate cannot be used as a currency is that each unit (e.g. block of land, portion of a building) is too large in scale. This prevents real estate from becoming a medium of small daily transactions such as shopping in groceries.
What if, however, we are able to buy and sell pieces of land in an extremely tiny scale? If people are allowed to exchange square-millimeters of land at a time, each real estate transaction will be able to involve only a fraction of a dollar and thus be carried out in a far more casual way (i.e. just as simple as swiping a credit card).
Square-millimeter landlords are entitled to use these geographic fragments in any way they desire. A person, by making a sequence of tiny transactions, can expand one's own territory by literally "drawing" on a piece of land because each transaction is an equivalent of coloring a single pixel in an image.