A huge part of the tastes of Thai Food comes from the pastes that are used for cooking. These provide a wealth of flavor and for dishes that are cooked with paste, most of the chili heat.
Sauces are equally important for dips or for marinading. They are used to balance the flavors of the food before and during cooking.
The dips are just another level of taste to provide lots of choice for the diner at the table.