I would say that this statement is not true in any serious way.
For the statement to be true, we would have to assume that neither the US nor the Soviet Union would have used nuclear weapons in this crisis. While we may hope that they would not have, there is no evidence that that is the case.
When the Soviet missiles were discovered in Cuba, President Kennedy and his advisers all agreed that they had to be removed no matter what. They considered air strikes against Cuba and they considered invading the island. It seems likely that either of these actions could have triggered a nuclear war. Similarly, it seems likely that a Soviet attempt to run the blockade could have led to war. If the US was (as it appears to have been) determined to blockade Cuba, it would have had to attack any Soviet ship trying to break the blockade. This would have been an act of war.
There are many ways that the Cuban Missile Crisis could have led to an actual war. In such a war, it is likely that nuclear weapons would have been used. Therefore, the Cuban Missile Crisis was a real danger to the world.