There are multiple benefits of using Visual Workflow instead of Visualforce Page or Apex code. They are as follows:
To use Visual Workflow, no coding is required. This means even if you don't have experience in writing Apex code, you can still develop an application.
You can share your application with peers by creating packages.
Using Screen, Record, Fast, Field, and Choice elements, you can implement a complex business process to make sure that your users are entering data in the right format.
It also allows you to auto-submit records for approval.
You can also post a message on Chatter. For example, If an opportunity status gets Closed Won, post a message on the Account feed.
It allows you to embed your flow into a Visualforce Page. Then, using Force.com site, you can expose it for unauthenticated access.
You don't need to write a unit test class, and this is one added advantage over Apex code.
Salesforce allows you to update your flow into production org, but you...