A clarification on the Emacs Tutorial

[Sivaram Neelakantan]

So, I had some free time and was going through the tutorial and came
to this part

Note that a single C-k kills the contents of the line, and a second
C-k kills the line itself, and makes all the other lines move up.  C-k
treats a numeric argument specially: it kills that many lines AND
their contents.  This is not mere repetition.  C-u 2 C-k kills two
lines and their newlines; typing C-k twice would not do that.

Right, I *know* this,OK?  I understand this perfectly but could you
tell me what's that sentence "This is not mere repetition" for?  I
can't see what that sentence is trying to say in context.  If I remove
that sentence it makes perfect sense but maddeningly I can't figure
what that sentence is trying to convey.

Anyone?

 sivaram
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