It's not the same thing. They get something that they don't seem to have, a way to promote their browser.
Look at all the other popular browsers, they're all made by big, known companies (Apple, Google, Microsoft) or by the "community" (Mozilla). Apple and MS ship the browser with the operating system, Google offers it for downloading on many of its sites. The "community" places countless of "Get Firefox" links on countless sites.
"Opera? What's that? That classical piece of music mixed with lyrics? That's uncool. Ah, it's a browser? Who makes it? Opera? Never heard of them."
Now they're trying to get some publicity for free, and not only for free, but using a competitor's software as a vehicle. Weird to say the least.