Games not meant for the DS?

Look at that completely usable bottom screen!

There are some games, like SolatoRobo, which is a game designated for the DS, but uses none of the features of the DS. This is not uncommon either, as fairly many games have started this trend. But why?

It seems to me like a way of earning more money for a game, without using any of the features that the console has for it. It's a cheap and petty way to earn more money for a game that could be so much better, or so much different, with the stylus.

Zelda used all the possible features
that the DS had to offer

Pokemon and Zelda are games that incorporated the touch-screen very well, and through that had some pretty unique gameplay. In Zelda's case, the stylus-based movements are what paved for way for the Wii's motion controls. It bettered the games and made it fun, and dangerous all at the same time (*swings Wii-mote and shatters brand new flatscreen TV*).

But if a game is going to be made without any real use for the second screen at all, then why allow it to be published on the DS, and not, say, the PSP, or the GBA? It would make more sense for a game like Castlevania Dawn of Sorrows to be made into a GBA game. Adding crappy implementation of the touch-screen is just as bad.

Okami is a game designed around this touch-screen concept, and would be a great addition to the DS, because it uses the touch-screen all the time! It is actually the main basis of the game. Why can't other games do that? And if you are not going to implement any groundbreaking touch-screen semantics to the gameplay, then why the DS at all?