Benefits to writing a function as opposed to just doing everything in Update()?

Hi I have a simple question. Are there any benefits to writing a function for an action and then updating that function as opposed to writing things in Update(). Does anything change? Do functions maybe get called last? Example:

Update()
{
   if(Input.GetKey("s"))
   {
     crouch;
   }
}

as opposed to:

Update()
{
   function Crouch();
}

function Crouch()
{
   if (Input.GetKey("s"))
   {
     crouch;
   }

}

In this example there is no benefit to make another function. But if you have code that is used multiple times on multiple objects, it can be beneficial to make it into a function.

The function will run as soon as it is said to run. Then jumps back to run the rest of Update()