After going through the feature richness of Kotlin, it would be really helpful to compare it to Java. This is not to prove a particular language is more appropriate than the other, but rather to just list the differences to make the choice easier for different scenarios:

• Null safety: Kotlin provides a nice way to define and handle nullable types, whereas Java does not have a similar feature out of the box.
• Extension function: Java needs an inheritance to extend the class, whereas Kotlin allows you to define the extension function without inheriting any class. You can define an extension function for custom classes as well.
• Type reference: In Java, we need to specify the type of variable explicitly, but Kotlin will handle it based on the assignment so you do not have to define the type in all the scenarios.
• Functional programming: Kotlin is a functional language and provides many useful features for functions. Java, on the other hand, has started supporting lambda expressions.
• Coroutine support: Coroutines are lightweight threads used to handle asynchronous, non-blocking code. Kotlin support coroutines out of the box. The Co-routines are managed by users. Java, on other hand, supports similar functionality with multithreads managed by the underlying OS.

• Data class: In Java, we need to declare constructors, getters, setters, toString(), hashCode(), and equals() manually, while Kotlin does all that behind the scene.
• Smart cast: Java needs to check for cast explicitly, while Kotlin does this job smartly. 
• Checked exception: Java does support checked exceptions, whereas Kotlin does not support them.