Seems like it serves all the purpose in the world, as it doesn't allow you to get your fill. Instead, it builds your need to play it even more. After all, they want to push the frenzy to buy it, not fully satisfy your craving for free.
Yeah, as much as I think the idea of a demo sounds awesome, I have no concerns whatsoever. Plus, with it being an RE title, I'd rather just dive in directly.