“Push notifications are a powerful way for application publishers to engage users directly. Publishers can use them on most mobile platforms and at any time—you don’t need to be using a given application to receive them. They bypass spam filters and are frequently used to drive actions, like telling the user about a special discount, a weather event, or a financial transaction that needs to be confirmed.”
If you would like to know more about how to implement push notifications with Expo and how Courier can help simplify the process, check out this Step-by-Step guide I wrote about it.