If you buy the plushie, you get the corresponding pet. For me, spending real money for pets my characters wouldn't use and toys I'd throw in my Goodwill pile... not worth it.
I'm pretty "meh" about these pets, but I congratulate anyone who likes (and can use) both the plushies and the pets. And I'm sure if anyone just wants the pet, they'll have adorable animations and your enjoyment will be worth the price.
Also, there are plenty of kids in the world to give the plushies to. My sister-in-law is percolating one as we speak, so if I really want any of the plushie/pet combos in the future, I can pawn the real world toy off on the baby. Since its parents both play WoW, I'm sure they won't mind. :D