[wp-hackers] Question about use of while in 2010 loop-page and loop-single

[Claude Needham]

Forgive the question. But, I'd like to get some insight into why the
Twenty-ten theme uses the following in the loop-single and loop-page.

<?php if ( have_posts() ) while ( have_posts() ) : the_post(); ?>

Other themes I have looked at just use the_post() and don't include
the while mechanism.

I have a natural respect for the Twenty-Ten. So, I'm assuming there is
some behind the scene advantage to this approach.

I know this is probably glaringly obvious. But, could someone either
drop a hint, or point to a resource that would give me some insight
into this.

Thanks in advance,
Claude Needham