[nonameiguess]

It matters in discussion forums like this involving ordinary people. There are two reasons we might care about statistics and trends like this.

One, you're a public health official or maybe even just a voter trying to weigh various policy options or assess the success of what has already been done. In this case, sure, you have to care about national averages and other measures of central tendency and ways to characterize distributions.

Two, you're an individual American trying to figure out how much you should worry about an early death. In this case, national averages or even per-culture averages seemingly mean next to nothing for you. I can't speak for all Americans, but I expect to outlive the average by quite a bit.

For gun violence, it's often travelers and visitors worried they're going to get shot if they come to the US, and we're trying to tell them that whether they really need to worry heavily depends on where they're visiting. Even if they're actually visiting Chicago or Baltimore, gunshot deaths in tourist districts are damn near unheard of, and besides which, the vast majority of people ever killed by guns at all are either killed by themselves or someone who knows them. There aren't a whole lot of random stranger attacks happening anywhere.