When someone wants to use Extracted data to data drive Find Expressions, they have to do the following:

Set up a local Data Source
Extract the data from the input field 
Then use the extracted variable in a Data Driven Find Expression to locate the value and verify it. 

The problem is that a datasource is necessary for datadriven find expression to populate. Without a local or bound datasource, datadriven find expressions aren't available. This means that extraced variables can't be used.

--
Request - Allow data driven find expressions to be available without having to bind to a data source. Then find expressions will be able to bind to a variable if a variable is available.