Does the "FindControl" method search nested controls..I think it does

I've come across articles on the internet showing how to write a custom method that will find "nested controls" that reside inside templated controls such as the System.Web.UI.WebControls.CreateUserWizard control.
 
When I searched for a simple "TextBox" control that holds the users first name using the standard "FindControl" method of the "CreateUserWizard" control it found the nested TextBox with absolutely no problems.
So I am curious as to what scenario calls for a custom method to find "nested controls" when the standard "FindControl" method seems to handle this need.
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