Why is it important to use fillings, coating/icing, glazes or decorations for pastry products​

Frosting improves the cake's appearance.

Explanation:

Special occasion cakes become more festive with frosting and decorations; and, Frosting improves the keeping the qualities of the cake by forming a protective coating around it, sealing in moisture and flavor and allowing it to be eaten over a couple of days.

only #2 represents an object at rest on a table.

in #1, there is no normal force due to the table; the object is accelerating downward.

in #3, the vertical forces are not balanced; the object is accelerating downward.

in #4, neither the vertical nor the horizontal forces are balanced. the object is accelerating upwards and to the right.