What's the use of Application Starting Point?

I've read this article, but not sure about the purpose of ASP:

http://support.Winhost.com/KB/a635/what-is-the-application-starting-point-tool.aspx

Can't I just simply create a folder and upload whatever files I need to this folder and run an asp.net website from this? What does the Application Starting Point do for me?
Thanks.

 

The application start point allows you to set sub directories as their own IIS application.

This treats the folder as if it were its own root which is required by web applications and also allows you to structure your account in such a way that you can host multiple web applications on one hosting account.