Many Textpattern blog templates use this technique, which is where I first came across it. The H1 header at the top of the page is also a link back to the home page. Even the default template uses it.
I used it without thinking on a few minor sites I have and it seems to work very well so I tried it other sites with good results and then on my main site. Yahoo seems to hate it, Google may like it, but this may be on the move which is why I am experimenting with removing it.