While the 80 garden is stamina inefficient, so is 2-1 and the 12 stamina garden compared to 12-3. The 80 garden not only gives you 3-4 manyus, but they are all lvl 20 and more often than not 1-2 lvl 100s. And you also get Ampys, which in all honesty is a great thing because you cannot get them from anywhere else at the moment.