A food product such as whipped cream provides a good example. Anyone can buy whipping cream, vanilla, and sugar and mix up a bowl of whipped cream. But it's faster to buy a can at the store. The major point to remember is that most purchases of aerosol products are done for convenience and not necessity. Another example is the use of roach sprays.
People prefer the convenience of aerosols because they are quick and effective.
Unfortunately, most insects quickly develop resistance to these sprays. This leads to ever increasing dosages and the need for newer and stronger formulations each year. Few would consider the time honored method of mixing boric acid with cacao powder and sprinkling this powder around. While boric acid is an effective insecticide to which insects do not develop tolerance, its action is slow and its application messy. Concerns over VOC emissions associated with the propellants used in hair spray lead to the development and acceptance of the hand pump spray unit.