The things we use it for most is whole roast, like a strip loin or lamb leg. Season and cryovac it, let it go for 12 or so hours, then give it a sear to finish. Also, it's really good for confits. One of the main uses though is to cut down times on the line. If we take our chicken, break it into a skin on breast and a thigh/leg roulade, then cryo it, cook it sous vide and shock it in ice water. They'll hold like this for a week, and when needed on the line, we just hold them in the water at serving temp, then give it a sear to serve, bringing the service time to a few minutes instead of 15 to 20. This will work for steak, pork, and some sturdier seafood. I don't see it as necessary for veg, though some chefs swear by it as well. To me it's just extra labor.