Sugarcandy Moutain gives Jones an advantage because the idea is designed to lull the animals into working and toiling without dissent or question. As propounded by Moses, Jones's pet raven, Sugarcandy Mountain is where the animals go when they die after they have worked and suffered without question and without discussion. Sugarcandy Mountain is the animals' reward for all of their hard work and struggle.
This benefits Jones by ensuring that the animals work towards a mythical end. Jones can take advantage of the animals' labor and exploit them while they are focused on the reward of "the afterlife" offered in Sugarcandy Mountain. Jones's advantage lies in how he is able to benefit from the animals' hard work without any resistance from them. Sugarcandy Mountain is the reward for their work, a reward that Jones himself does not have to deliver. The need to present Sugarcandy Mountain as a way to lull the animals into working harder and doing so without question is how Jones is able to make the idea work to his benefit.