[![Bidirectional shift register][1]][1]  
<sub>(source: [edu.au](https://www.ee.usyd.edu.au/tutorials/digital_tutorial/part2/pics/regist06.jpg))</sub>  
This is the sort of bidirectional shift register, I'm talking about.

I understand why the normal right shift is useful, but when you shift it left, all you're really doing is sending the data input straight to the output.
Is there a useful reason for shifting bits in this manner?
EDIT-
I'm trying to understand how the when shifting to the left, the value int left most register is outputted at the right most end. It makes no sense.
Shouldn't the output be what the input is when shifting left?


Thanks!
 [1]: https://i.sstatic.net/a8x7M.jpg