Do you work at an advertising agency? probably not. Do you do freelance volunteer for for some of their clients? Yes you do.
I am presuming that you own a t-shirt or hat. It's probably got something on it: a team logo, a movie quote, something like that. You probably paid quite a premium to have that logo included on the clothing: plain t-shirts are $10 for a five-pack. And when you wear it it's a conversation piece. It says to the world I AM A PORTLAND TRAILBLAZERS FAN, or I AM ON COORS LIGHT BEACH PATROL or HEY REMEMBER VANDELAY INDUSTRIES? IT'S FROM SEINFELD. EVEN IF YOU WATCHED THE SHOW IT'S NOT THAT FUNNY.
I own a bunch, mostly video game novelty t-shirts. (Don't act so surprised!) I didn't buy them from Nintendo. But they advertise Nintendo, even though Nintendo and its various PR branches had nothing to do with it. And, probably, are a mite peeved that others are selling their characters and not paying them for it. That mite peeved is offset by the free publicity they receive.
Think of Coke: you've heard of it, yes. You would have heard of it even if they completely ceased any and all advertising spend last year. That would have saved them a lot of money. But they keep on spending, hammering home new "stories" about their brand. Because otherwise it's sweet brown water, a few cents of high-fructose corn syrup mixed in with seltzer. Coke's advertising isn't the spotlights around a movie premiere: it's the lasers at a laser lightshow. That's all there is to it.
Nintendo is in a different boat, since they make a more tangible product with qualities that don't have to be spun out of gossamer imagination. They make games. But even they still would like to coast on free publicity. So HMV's holiday display is a welcome boon, I'm sure. Every HMV will have pcitures of (there's no picture with the article, but I'll take an educated guess here) Mario wearing a Santa hat posing with presents. Next to Lady Gaga and Adele and Kung Fu Panda.
The way most (most, not all: again, I know nutt-hink!) deals like this work, HMV asks Nintendo if it can borrow Mario for this campaign, and Mario says yes, and no money changes hands. Because whose hands should be doing the receiving? Mario benefits from the exposure. HMV benefits from ancillary whuffie spilling around the plumber's aura. It's that 21st century line between product placement and synergy, between buying in and selling out, between being seen and ... and...
Wow, that's sad. Can't find a counterbalance statement for that.