Is this your first time seeing this kind of advertisement? Gamecube games came with stuff like this all the time. This one actually seems to be pretty well done, since it's made in a 100% tongue-in-cheek manner, did you actually read it?
I see what they mean, kinda. I'm playing it right now and the game has a serious Super Mario Sunshine aesthetic inspiration, down to the use of paint and the Shine-looking Paint Stars.
Plus, never forget:
Plus, you know, it's marketing. So they're going to try to get fans of a successful game to buy a new game.
Great cast of characters like paint can and 14263 generic toads.
If you like thick sticky stuff
Then you'll LOVE
Paper Mario: Color Splash