why should you care? well, that's up to you. but one thing sIFR solved (or attempts to) is those questions on accessibility with rich content. since the text you are replacing is still there, it should present a more accessible site in the event you needed that (i.e., text readers, etc.). of course ymmv on your particular implementation.
pretty cool. the sample indicates that hyperlinks work, but i didn't see it working in the sample...maybe a slight bug, but great start nonetheless.