In cases where there are conflicting type names, using an alias will save you from having to use fully qualified names. The name TextBox for example is used in both of the following namespaces.
System.Windows.Forms.TextBox
System.Web.UI.WebControls.TextBox
Relying on the order of the using declarations would be fairly brittle and would only help with one of the namespaces. Better would be to assign each of the namespaces an alias.
