[dragonwriter]

> What's the point of having nuclear weapons and not telling everyone?

The point is so that:

(1) You can maintain the highest ground in proliferation discussions focussed on rivals, and

(2) Reveal your own weapons quickly if the geopolitical situation shifts (either as deterrence or, should the situation shift too quickly for that, direct use to blunt an existential threat.)

> The entire point of nuclear weapons is to deter attacks.

No, it's (as with any weapon) to provide the capacity to destroy the enemy if needed.

Like any weapon, this capacity can be publicized to deter attacks, but that is not the sole purpose of the weapon, and it can't be, because deterrence cannot work if it is perceived as the sole purpose of a weapon.