Yes, it was.
At this time in the Cold War, Intercontinantal Ballistic Missiles (ICBMs) were not yet fully developed. This meant that the Soviets did not have large numbers of missiles that could strike the US from Soviet territory. The only way for the Soviets to launch a massive nuclear strike on the US would be through the use of bombers. This would, of course, be dangerous, but bombers can be shot down.
If the missiles in Cuba had been fully installed, the Soviets would have been able to reach practically the entire United States with missiles. The only major city that would have been out of their range was Seattle. This means that the US would have been much more vulnerable to attack.
Therefore,Soviet missiles in Cuba would have been (at least in 1962) a bigger threat to the United States than the US without missiles there.