It's 30 dollars for the full game though, not just the Alpha phase.
So when it's finally done at some point you have the full game. It's like a pre-order only you get to play the buggy mess instead of just knowing you paid for something that might not happen.
But the current state of the game does in no way garner enough interest (for me at least) to put down a pre-order at $30. Compared to something like what Don't Starve presented during beta and their price-point it's just ridicolous.