1. Sous-vide offers precise (and easy) temperature control
One of the biggest concerns while infusing canna-oil is the temperature -- if it's too cool, the THC will bind to the oil at a diminished rate (or not bind at all), and if it's too hot, you're vaporizing some of the psychoactive ingredients and losing potency.
"As a general rule, a higher temperature leads to a faster reaction rate and therefore requires less cooking time to be activated; it should be noted, however, that temperatures above 140 [degrees] C run the risk of beginning to vaporize compounds out of the mixture and temperatures below 90 [degrees] C may not lead to significant chemical conversion on a time scale of less than 24 hours.” -- ScienceDirect and Perrotin-Brunel, H, Buijs, W, Spronsen, JV, Roosmalen, MJEV, Peters, CJ, Verpoorte, R, Wikamp, GJ. via Wikipedia