Well, only the fact that HTML parsers will actually parse the HTML for you - whereas any regex-based solution will only handle a subset of the possible HTML and will prove extremely fragile if the HTML ever changes.

You might like to take a look at the section "How not to parse HTML" in chapter 8 of Data Munging with Perl.

--
<http://www.dave.org.uk>

"The first rule of Perl club is you do not talk about Perl club."
-- Chip Salzenberg