Will 'Wii Fit' Fit?

Wii Fit is already a bona fide hit in Japan, selling through over a million copies in a month's time. But, "hardcore" gamers here in the US seem dead-set against it, deeming it too casual for their tastes. Time will tell if Wii Fit becomes a hit here, as the game comes out in Spring (April is the current rumor). But, my bet is that it'll be just as successful as the Wii itself. I'm of the opinion that the dichotomy between "casual" and "hardcore" isn't as pressing as whether a game is enjoyable. Mario Party will likely go on forever just because people have fun playing. I'm interested in what Wii Fit has to offer. From all accounts, the game really is capable of giving you a great workout (which isn't hard for me to believe at all after playing Mario & Sonic). Here's a preview from GameTrailers.