Serverless functions are a great option for backend services, especially when used with mobile apps. Using Kotlin as the programming language can simplify development and improve security. A serverless function hosted on IBM's Cloud Function can be created by adding dependencies to a Gradle project, creating a new Kotlin file, and deploying it using bx wsk action create. Once deployed, the function can be invoked using a URL or through an Android application. By using a serverless function, developers can avoid scaling concerns and focus on writing logic-free code. The use of Twilio's SDK simplifies SMS message sending, and multiple functions under the same namespace make deployment and maintenance easier.