Disadvantage, in order to keep feeding people as the population grows, you have to radically change the environment of the planet. Advantage, especially if you grow grain, you can create a food surplus, which makes cities, possible, and also the specialization of labor. Like, in the days before agriculture, everybody's job was foraging, and it took about a thousand calories of work to create a thousand calories of food. And it was impossible to create large population centers. But if you have a surplus, agriculture can support people not directly involved in the production of food. Like, for instance, tradespeople, who can devote their lives to better farming equipment, which in turn makes it easier to produce more food more efficiently, which in time makes it possible for a corporation to turn a profit on this 99-cent double cheeseburger. This is delicious, by the way.