Wii play is an odd one because people view it in the same way they view Carnival games and Sports party and all that wank.
Thing is, Wii play has a similar amount of content, and is usually slightly better content than those games, except it costs you only 1/4 of the price, Wii Play is MEANT to be shallow.... and it's price reflects how much was spent developing it compared to other games. It costs all of £5 or $10.... unlike the other, roughly equal in content games, that cost at least standard budget price (which in the UK is £20, so 4 times as much... not sure how it works out elsewhere) if not full price, which is £30-35.
For instance, the Xbox live version of Geometry Wars Retro Evolved can be bought as a disc Wii game... the XBL version has very little content really.... so imagine that as Wii Play..... if the Wii version on disc, costing budget price (£20 / 3* as much money) had exactly the same content then it would be equivalent to some of the Wii shovel ware.
However, there is a hell of a lot more content in the Wii version las it has the same as the XBL version, plus a multi player version of it, plus over 60 other different levels to go through with varying difficulties (and even more if you buy the DS version and connect them together) so it's price is justified.