The quote words operator is just a typing convenience to let you omit the commas and quoting. Instead of typing:

@array = ( "dog", "cat", "bird" );
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You type:

@array = qw( dog cat bird );
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The qw() will break up the thing inside it and give you back a list of the things between the whitespace (and because of that, you can't use qw() with values that have whitespace in them.

That's it.