Why are procedures (closures) needed in programming?

Question

ruby

Why are procedures (closures) needed in programming?
Here is the ruby ​​code.
1) - percent. function.

var = Proc.new do
puts 'Как-то так'
end
var.call => Как-то так

2) regular function (method)

def var
puts 'Как-то так'
end
var = > Как-то так

Here the second function (not procedural) is clearly better than the procedural function. And why do we need these percentages. ?

Answer 1

You have misunderstood the question. By giving an example, you did not reveal the whole essence of closures. Namely, that they can be passed as parameters to other functions/methods. That. the method can be internally extended by an anonymous function.
But this approach should not be abused.
In any case, closures or ordinary procedures/methods are the same approach --- a description of the program in steps: what and how to do to get the result.
It is much more interesting to describe the problem in the form of boundary conditions and obtain a solution without describing the algorithm (see Prologue), but this approach is very limited and resource intensive.

Answer 2

https://ru.wikipedia.org/wiki/First_class_functions