Why is it important to fit your persuade appeal to your audience interest?

To write about a subject that will make people feel as if their safety ,security or health is in danger. 

Example:Mike used appeal to fear in his writing ti make his readers think: if they did not buy a Snuggie the they would never be safe again. I got that from wiki answer if that helps.

Idont get it at all sorry

How i posted to know cuz