• to initialize (assign) fields (identifier, variable) in WORKING-STORAGE SECTION
• better than MOVING in PROCEDURE DIVISION. Since you are apt to remember to initialize when defining the fields themselves.
• very useful when you printing "headings"

Examples

...
WORKING-STORAGE SECTION.                           01 REC-CNT PIC 99.
01 REC-CNT1   PIC  99 VALUE 0.                     ...
01 REC-CNT2   PIC  99 VALUE ZERO.                  PROCEDURE DIVISION.
01 REC-CNT3   PIC  99 VALUE ZEROS.                     ...
01 REC-CNT4   PIC  99 VALUE ZEROES.                    MOVE 0 TO REC-CNT.
...

More Examples

WORKING-STORAGE SECTION.
01 WORK-AREAS.
   03 WS-FLAG            PIC  X    VALUE  'M'.
   03 TAX-MONTH          PIC  X(3) VALUE  'APR'.
   03 BLANKS             PIC  X(3) VALUE  SPACES.
   03 TAX-TOTAL          PIC  9(5) VALUE  SPACES.  <---- Wrong! 

Examples for Headings with very long Literals

000100*A---B--+----2----+----3----+----4----+----5----+----6----+----7--
       WORKING-STORAGE SECTION.
       01  HEADING       PIC  X(73)       VALUE            'MONTHLY TRAN
      -    'SACTIONS FOR ...............................................
      -    '.'.

How to handle Decimal Point

   03 TAX-RATE           PIC      V99  VALUE  .06.
   03 TAX-RATE2          PIC      V99  VALUE  0.06.
   03 UNIT-PRICE         PIC   999V99  VALUE  150.20.