There's a pretty big difference in China sending a couple of warships to the gulf and USSR setting up a nuclear missile base with missiles pointed at the US on Cuba.
Nuclear missles or "90000 tons of diplomacy" are both certain kinds of deterrence, nothing more, nothing less. If US does not have those carrier combat groups, China wouldn't care either.
I'm going to sound like an apologist, but the Cold War nuclear miltary-political calculus was very different pre-ICMB+MAD on both sides of the Soviet-US split.
SLBMs were just being developed in the early 60s, and so Cuban-based missiles represented a novel, more credible first-strike threat given distance (~20 minutes flight time).