That's how academic papers are done. One reason is that it's more complicated to do mathematical equations and such in HTML (we don't even talk about text) than it is to simply use LaTeX.
I understand the need for proper formatting in academic papers, but it wouldn't hurt anyone to provide a text copy after the fact.
If someone needs a formula they can render the pdf. But a secondary text copy can be more easily indexed, searched and viewed on any kind of text-viewing device... it's just a million times more convenient.
It "hurts" in that it takes time. It's also not just math, but figures as well - diagrams and experimental results. There are automatic Latex-to-HTML programs, but their results are not pleasant. And I have difficulty putting up things that are ugly.
