Can Extended Events be used instead of Auditing?
Extended Events can capture all the events that are traced by auditing?


Yes and no. The built in auditing framework is built upon the extended events framework. This means any of the built in auditing will be serviced via the XE framework, assuming it is setup.


  Can we get all the functionalities of auditing just by using XEvents?


You can get most, but it's not 100% coverage. Since the auditing is built upon the framework there would be the possibility, however not all auditing events have a 1 to 1 or even a correlated mapping to non-auditing based extended events.