The mortality rate is much higher than the .01% that is the flu. Right now it appears to be about 2%. The only question is whether it will fizzle or go widespread. If it fizzles then yeah, no big deal. If they fail to contain the spread, it will kill a whole lot more people than anything we've seen since the 1918 outbreak.

I have no idea about the containment issue, but it's clearly not a trivial concern or China wouldn't be closing down entire cities the size of Chicago and Houston to prevent its spread.