We suspect that this new upcoming feature will allow you to purchase quest rewards directly using Farm Cash, if the price is right of course. Often times players miss out on quest rewards when they are unable to complete quest requirements within the time frame allowed and have never had the option of purchasing the missed quest reward offerings. Additional quest rewards were only available for purchase using Farm Cash if a player had completed that particular quest segment. The prizes for future segments in that particular quest that the player didn't advance to were unavailable for sale.
This is one way to directly purchase that must-have item that you may be dying to have, but unwilling to quest for, but only time will tell if it's worth your Farm Cash. More news on this upcoming FarmVille feature as soon as it's released. Stay tuned.