The world is too complex in order to be fully described mathematically. But at least with the help of math (and statistics is math) some aspects of the reality can be described in a simplified model so that you can derive certain insights and based on them you can make decisions.
If you think back at the Middle Ages in the 14. century when the sovereigns and their counsels had no clue about science or math and thus not much knowledge how to protect the population it's no wonder that a third of the German population has died due to the plague.
Do you have a link? Hendrik Streeck who recently made the Heinsberg studies said that at the end of the year there will be no significant increase and was heavily criticized by other experts.