What is the provided functionality of Angular-UI Jquery Passthrough and angular.element()?
Are they interchangeable? does jQuery passthrough any additional options over angular.element()?
Any good examples out there that might demonstrate the power of each in an ng-app?
You are confusing 2 unrelated pieces of code.
Passthru is just a simple wrapper that enables you to call any jQuery method on a DOM element without creating a new directive.
angular.element() is a javascript method that returns a DOM element. If you injected jQuery first then angular.element() === jQuery() ==== $()
Passthru does not do anything special, and angular.element() isn't needed because a $element is already provided by the linking function.