Benefits are the “buy now” decision makers for your audience. When hearing or seeing the benefits, people will make a subconscious decision as to just how valuable that benefit will be to them. If the beneficial value is high enough, they will buy!
List all the features of the app and write a paragraph for each, explaining the benefit that the user will receive by using the app.
For example, "Password keychain: using the same password for lots of websites is very insecure. This app will let you store a different password for each website, but you'll only have to remember one; The app password!"