I don't understand what Windows Workflow gives me

Take this for a simple workflow. An employee creates a document, from here the document goes to level one supervisor for approval, if approved it goes to next level and so on until final approval and file repository. If not each level can kick back to previous level.

What does Windows Workflow Foundation give me that I can do on my own? Those sound like simple rules to code so I'm not sure what I am gaining with WWF.

Thank you.

EDIT: Now if that flow chart that I make in Visual Studio actually created a wizard or something that I could use that'd be different. I don't know that would even be coding but at least I could understand it better.

Having never used WF myself, allow me to direct you to those who have:

• Paul Andrew, SharePoint Dev PM, on What to use WWF For
• Why Workflow? from James Conard's former MSDN blog
• "Italian Railway Police Automates its Document Management and Workflow", from MS Case Studies

Here's a quote from that last article:

WF controls the approval flow, creates Web pages on demand to secure human approval for an action, and controls SharePoint actions through a Web service.