I've started playing through World 2 today and I have just got the 2 power stars and 1 medal on Hightail Falls Galaxy - the one where you first encounter the peppers with Yoshi.
Now on the first ascent on the left, there is an additional pepper that is a little more difficult to reach. When you do get it, you can climb a little higher and reach a new platform.
The thing is, the platforms seems pretty pointless. There is an old penguin on top that tells you how awesome Coins are, and nothing else. What the hell is going on with that guy? Or do I return there somewhere later in the game?