The user interface (UI) and user experience (UX) of an app are important for several reasons. First, they can make or break the first impression users have of the app. A well-designed UI/UX can make users want to use an app, while a poorly designed one can discourage them from using it.

Second, the UI/UX can affect how easy or difficult it is for users to use an app. A good UI/UX will be intuitive and easy to use, while a bad one will be confusing and hard to use. This is important because users are more likely to abandon an app that is difficult to use.

Third, the UI/UX can influence how much users enjoy using an app. A well-designed UI/UX can make using an app a pleasant experience, while a poorly designed one can make it a frustrating experience. This is important because if users don't enjoy using an app, they are less likely to continue using it.

Overall, the UI/UX design are important factors to consider when designing an app. They can make or break the first impression users have of the app, affect how easy or difficult it is to use, and influence how much users enjoy using it.