Barcode is optical. Takes a laser "reader" to be passed over the printed bar code. The reader has to be right next to the code to read it. By the nature of the design, both the barcode printing and the reader to read it HAVE to be visible.
RFID is electronic. RFID patches can be hidden on or in all sorts of things. The readers can also be hidden. They can be several to many feet away, depending on the sensitivity of the reader. While RFID does have some inventory tracking uses, the big use of RFID is so that "Big Brother" -- corporate or government -- can track YOU, by what you are carrying, what you are buying, what you are discarding. The ideal is to have an RFID chip embedded in YOU.
Scenario: You buy something with an RFID chip. The store scans it and ties its code to your credit card or the RFID code in the currency you paid for it with. Later, you happen to dispose of the item in an "environmentally inappropriate" manner. (You throw the worn-out batteries into the trash instead of making a special trip to a recycling center.) The garbage truck RFID reader pings everything it picks up and sees that a forbidden object is in the trash, and its RFID code points to you. In a little while, there is a knock at your door, "Citizen, your papers (ID) please..."
Rent the Tom Cruise movie "Minority Report" to see what your rulers have in store for you with RFID tracking technology.