I think it is basically a small collection of mini-games...
It is fun to pull out every once in a while

Free Wiimote controller.

The Wiimote still cost $40.

Considering I've seen people buy 3 copies of the Wii Play bundle during the holidays it isn't surprising.  Anything Wii related is always sold out during the holidays, so if the base Wii Remote is out of stock people will just buy the Wii Play bundle.  Even outside the holidays for the first year or two things could be pretty sparse, so they'd take what they could get.  Not to mention it's a pretty easy sell for parents that you get another game for just $10.

can`t understand how nintendo thinks XD

I understand your thesis

I expected to be able to say with complete confidence that the three games didn't really make a difference, and that they could have been swapped out with any other three games and sales wouldn't have been affected more than maybe a couple % points.

I think theres something to it though, not so much the tanks, but the shooting range and table hockey are a couple of games that probably inspired a lot of impulse purchases.  They see the game with the Wiimote included, pick it up and see shooting range and table hockey on the back and the purchase is almost automatic.

Edit: except I just looked at the back of the case and table hockey isn't featured very prominently at all.  In fact now I think pool and ping pong might have played a larger roll.  Ping pong, Pool, and shooting range are all highlighted well on both the front and back of the case.

wow someone wanted to buy it without a wiimote?

must be a pretty good game after all.

I reviewed this game for VGChartz and the conclusion I kept coming back too was: it's a bad and shallow game... but it's fun.

And I think as hardcore gamers see it, fun is not a measurable stat, so they ignore it, they look at graphics, sound, depth, etc. but forget that games should be about fun.

Hell it's a GAME and you PLAY it.

It sold a lot because it came with a free controller. That's why everyone I know got it, at least.

I think people just wanted a new game to play with their miis on. They saw the word Wii and remembered how much they loved wii sports and then saw it contained a wii remote causing it to become an instant purchase.