The answer to that would be very subjective, depending on the person's beliefs and views about life. If you are fatalistic, I do not think it is necessary to purchase one. In my case, I don't really, because it's costly, and so far, I am still alive and kicking.
However, for most Japanese, they always do. For safety reasons, though, It's costly. Nevertheless, we can not predict what will happen in the future. So, to be safe, go for it.