What is the purpose of Unit-returning in functions

Question

From the Kotlin documentation:

If a function does not return any useful value, its return type is Unit. Unit is a type with only one value — Unit.VALUE. This value d

Answer 1

UNIT actually contains valuable information, it basically just means "DONE". It just returns the information to the caller, that the method has been finished. This is a real piece of information so it can be seen as the return value of a method.