Plastics being lighter as compared to metals are used in cars, aircraft and spacecraft too.
Containers made of plastics are easy to handle. It is most convenient to store food items, water, milk, pickles, dry food.
Plastics are poor conductors of heat. Hence, handles of utensils are made of plastics for safety.
Since plastics do not get corroded easily, it used to store various kinds of material, including many chemicals.