When a person argues that a product should be used because "everyone else is doing it," what is this appeal called?

The scenario described in the question demonstrates a Bandwagon Appeal, which centers around the idea that one should adopt a belief or take action simply because it is a popular choice among others. This technique taps into the human desire for conformity and the fear of missing out, often suggesting that if many people are doing something, it must be right or desirable.

In persuasive communication, the Bandwagon Appeal is an effective strategy because it leverages social proof, implying that widespread acceptance of a product or idea validates its worth. This psychological phenomenon can lead individuals to make choices based on the behaviors and opinions of others rather than on personal reasoning or evidence.

Recognizing this type of appeal helps individuals critically assess arguments and make informed decisions without being swayed purely by popularity.