While GTA won't appeal to grandma, it did appeal to a lot of "tough" types who thought games were too detatched from reality. GTA's urban backdrop and dark humor is really what made it a hit.
Here casual means "tough dudes who don't play games much but like to keep it real" instead of "soccer moms and grandma."
There is no such thing as a console war. This is the first step to game design.