I still think that it´s a pity to make an 8 bit game on 16 a bit machine. The same story with Uwol, if anybody heard about it. To ´waste´ MD carts (for physical releases) is not that great in my opinion (if the carts are new, then it´s okay maybe, if it´s not as terrible as the 1985 Alternativo material).
I think it's a good idea in the sense that the MD has a bigger overall audience, and it could expose some of those gamers to SMS games that they might not have heard of before. Also, I suspect that this game might be technically beyond the SMS capabilities, for example the number of colors used for sprites.
Exactly, technically it's not an 8 bit game, depending on which characters you choose, there can be more colors on the screen than what the SMS can display. And besides bigger audience, it's also much easier to create such a game on the Megadrive, there's less need to optimize.
As for "wasting" MD carts, there are lots of shitty loose games that could this way get a better fate than the trash bin !