quick question about an example in one of the tutorials

In the binary tree tutorial, i am having a little trouble understanding one part of the code.

Code:

node *btree::search(int key, node *leaf)
{
  if(leaf!=NULL)
  {
    if(key==leaf->key_value)
      return leaf;
    if(key<leaf->key_value)
      return search(key, leaf->left);
    else
      return search(key, leaf->right);
  }
  else return NULL;
}

why is it neccessary to use node(a struct) as the return type? (rest of the code is in tutorial, too long to post )
instead of using something like this, and changing the rest of the code to match it.

Code:

int *btree::search(int key, node *leaf)
{
  if(leaf!=NULL)
  {
    if(key==leaf->key_value)
      return leaf;
    if(key<leaf->key_value)
      return search(key, leaf->left);
    else
      return search(key, leaf->right);
  }
  else return NULL;
}

just curious, all i need is to be pointed in the right direction, thanks in advance

If you return the node pointer, it makes recursion easy. What sort of int pointer would you have it return? If you did return an int as some sort of identifier, you would have to re-search the list to find the int, which would lead to bad recursion, seeing as this is a search function.