Why do we need exploratory testing?

At times, exploratory testing helps in revealing many unknown and un-detected bugs, which is very hard to find out through normal testing.
As exploratory testing covers almost all the normal type of testing, it helps in improving our productivity in terms of covering the scenarios in scripted testing and those which are not scripted as well.
Exploratory Testing is a learn and work type of testing activity where a tester can at least learn more and understand the software if at all he/she was not able to reveal any potential bug.
Exploratory testing, even though disliked by many, helps testers in learning new methods, test strategies, and also think out of the box and attain more and more creativity.