Upvote:7
The Wikipedia article may have painted an overly simplified impression. In the age of the nuclear arms race, the scale of a capability was a vital aspect of consideration. As unthinkable as it may be to us, destroying one city vs destroying one hundred cities is not a trivial difference in military strategic planning.
What the passage you cited failed to mention is that, at the time, the US had a massive advantage in first strike capabilities. Despite the panic over a supposed "missile gap", the US in fact had many times more operational ICBMs than Russia: some 170 vs perhaps 20. Moreover, the US had missiles deployed in Turkey - right under Russia's underbelly. True, they could not eliminate a submarine based second strike, in the unthinkable event that a thermonuclear war breaks out despite MAD, the US would've had a major advantage.
Deploying the missiles to Cuba was, therefore, a way for the Soviets to even the scores a bit, so to speak - the Soviet answer to American missiles in Turkey, if you will. Due to Cuba's proximity to Florida, the missiles put most of the Continental US within the range of Soviet nuclear missiles (as opposed to the unreliable and numerically limited ICBMs).
Furthermore, Soviet leadership reasoned that this gave them a bargaining chip to demand concessions in exchange for leaving. And in the event, the Kennedy administration agreed to retire the US missiles in Turkey.