when one or 2 words change in a long or dense line, it's nice to have the specific changes highlighted
imagine a for loop in which a variable (used on every line) was renamed, and buried in the loop an assignment changed slightly (eg, + became -). with a standard diff, it's really hard (for me) to pick up the minor change. with word by word diffs, it's pretty easy
(i use netbeans diff, not this tool, but they appear similar)
