What is the primary use of a cruet in a restaurant?

A cruet is primarily used in a restaurant to hold condiments for table use, such as oil, vinegar, salt, or pepper. Its design typically features a narrow opening for easy pouring and a shape that allows it to be aesthetically pleasing while remaining functional on the dining table. This allows diners to enhance their meals with various flavors and seasonings to suit their personal preferences.

The other options do not accurately represent the role of a cruet. It is not utilized for holding sauces intended for cooking, as these generally require different types of containers that can accommodate larger quantities and are often stored in the kitchen. Similarly, while keeping food warm is essential in the dining context, it is typically managed with warmers or chafing dishes rather than a cruet. Finally, a cruet is not designed to serve desserts, which are usually presented in dedicated dishes or containers appropriate for sweet items.