<Lambdas assigned to variables in Kotlin. Why?> I ...

# stackoverflow

[user]

Lambdas assigned to variables in Kotlin. Why?
I noticed that I get the same effect if I define this trivial function:

fun double ( i: Int ) = i*2


and if I define a variable and assign a lambda (with an identical body) to it:

var double = { i : Int -> i*2 }


I get the same result if I call double(a) with either declaration.
This leaves me confused. When is it needed, recommended, advantageous to define a variable as a lambda rather than define a function to it?