You're right, it does much the same thing, but this works on external sites so a webmaster doesn't need to create a bunch of anchors to specific information on a page. Instead you can link to any site and force the browser to highlight/jump to an arbitrary location on that external site.

It's the kind of thing I'd disable because of the privacy leaks it makes possible (Ctrl-F on the new page works just as well and keeps the user in control), but I can see how some people might like the extra convenience (when it's not being used maliciously to collect sensitive information from otherwise secure websites).