Also, I don't like the implication that "casual" means "bad". I'm sure you could find a better word to go there, like "questionable".
The problem is that the term is almost universally used as a euphemism for "piece of crap." Some exceptions exist, such as PopCap games, but usually when someone calls a game "casual" they basically mean "shovelware." Perhaps this isn't unjustified: most "casual" games are me-too titles that were clearly made on a small budget by a D-List team. This is in contrast to the average "hardcore" title, which is a me-too game made on a unnecessary budget by a bloated team.
In the PC downloadable industry, it has a whole different meaning. "Casual" in that sector means Hidden Object Games, Match 3 Games, Time Management Games, Word games, Light Sim and Adventure Games... yeah, like Popcap. Actually, some of these PC franchises have crossed over to the Wii and DS platforms, like Mystery Case Files, Women's Murder Mystery Club, Cake Mania, Escape From The Museum, and even Cate West: The Vanishing Files, to name a few. In fact, this "Casual" PC genre is seeing hundreds of new games a year (most of them, admittedly, very much clones within their genres), with a typical consumer of a 35 yr old, 45 yr old + woman.
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Just wanted to chime in to show an alternate meaning for the word casual outside the strict confines of hardcore console gamerism.