The advantage of the sous vide method is that the temperature is the same on both the outside and inside of the food, i.e. you can cook the inside at the desired temperature without overcooking the outside; this also means that the food is juicier.
Another advantage is that there is no reduction, i.e. evaporation from the raw materials in the bag. Meat and vegetables that are left for a long time (over 6 hours) become more tender as collagen and other proteins dissolve.
Pieces that are often perceived as tough can therefore be served tender even though they are still pink. The disadvantage is that there will be no frying surface on the outside.
As the food is vacuum packed during cooking, and can be refrigerated sealed, it has a longer shelf life as the food does not come into contact with oxygen. This is advantageous for catering operations, for example.
A disadvantage of sous vide is that the attractive browned frying or grilling surface of meat and fish dishes must be done separately. This is best done before serving, e.g. in a hot frying pan or in a salamander, preferably on a very high heat for a very short time (30 seconds) so as not to heat up more than the surface itself.