After exercise 6

Okay, so after the assignment and the exercise #6..
I think I finally start to understand something at least.

First of all, Binary Search Tree seems like a better structure than just the Binary Tree.
Obviously, that must be the reason there is a separate name for Binary Search Tree.
So what is this Binary Search Tree?
The items in tree is in order.
By that means, the smaller items are located in the left children of a root, and the larger items are located in the right children.
Of course, the children have the same behavior of having smaller items in left branch, else the right branch.
I like this structure because unlike the normal Binary Tree has its values randomly everywhere, Binary Search Tree is more neat when you see it.

However, I still don't understand the use of the Tree nodes.
Yes, the Tree nodes represent the hierarchical data and it makes the data more easily searchable.
But what is the practical use of it?
Maybe I don't know this quite well because I am still in the learning stage..
Because the Wikipedia gave me an answer of a "workflow for compositing digital images for visual effects" as one of the Tree nodes' common uses.
..Just to be honest, I don't really want to know about it, haha.

P.S. Oh wow, I didn't know BST also applied to strings as well!
       Cool stuff, lol