While meat is typically the most common food item to sous vide, it's not the only ingredient that adapts well to the cooking method. You can also sous vide other foods like root vegetables, fruit or heavy purées; some people even use sous vide for tempering chocolate and custards, pickling and fermenting, and even making omelets.
One reason so many chefs love the sous vide method is because it allows them to easily prepare large amounts of food. Redditor Kelsenellenelvial (he chose not to give his real name) is a sous chef for a large post-secondary educational institution in Canada and gave some compelling reasons to use the sous vide in lieu of traditional methods.
"[If I] have to cook a steak dinner for 100 people," Kelsenellenelvial explains via email, "getting all those steaks cooked the same can be tough. They won't be all the same thickness, and I might not have the equipment to cook them all at once. With sous vide, I can cook the steaks of various thicknesses all the same." Kelsenellenelvial explains that using the sous vide method not only cuts down on prep work, but also ensures an even and consistent cook for whatever you're preparing.
At home, you could use the same idea if you're hosting a large dinner party. Sous vide the proteins ahead of time and sear them just before service, for instance. But sous vide also is handy for easy weeknight dinners at home, too. Prep dinner for the week by cooking your proteins and refrigerate them in vacuum-sealed bags (they'll hold for several days). Then all you have to do is give them a quick sear at dinnertime.