This would allow easy manipulation of each nibble in the raw packet input in order to achieve a desired output value, since there is no "packet encoder" tool. It would also help to "show work" for visualizing each step in the decoding process.
For example, 0x0123 hex input should display:
(Hex:) [ 0 ][ 1 ][ 2 ][ 3 ]
(Bin:) [ 0000 ][ 0001 ][ 0010 ][ 0011 ]
These new input (Hex:) and (Bin:) rows should be displayed above the existing decoded (Bin:) and (Hex:) rows.