Shift Register and Feedback Node have the similar function that is used to store the data after execute the loop and transmit to next loop.
(Fig 1: Feedback node)
(Fig 2: Shift Register)
The result is the same, but Shift Register (Fig 2) has 3 store units.
(Fig 3: Feedback node with initializer one loop out)
But the shift register is faster than feedback node much. Compare the execute time by below code.
(Fig 4: Feedback node with timer--3301 mSec)
(Fig 5: Shift Register with timer--2698 mSec)