If wormholes large enough for humans to traverse exist, what could we use them for?

Now, I don’t profess to be an expert on General Relativity or Quantum physics, so take what I say here with a grain of salt. A bit of imaginative thinking, maybe.

We know it would take over 4 years to travel to Alpha Centauri at the speed of light through normal (flat) spacetime.

But, what if a wormhole stretched from a spot between the orbits of Jupiter and Saturn to Alpha Centauri and we could travel through it with a spaceship in say 30 minutes?

I, being a psychopathic megalomaniac who wants to rule the world at any cost, decide to secretly pack a spaceship full of planet destroying weapons and head for the wormhole intent on destroying earth. These weapons can travel close to the speed of light.

I’m not very bright, since destroying earth would destroy my own wealth and loved ones.

Now, I go through the wormhole, launch the weapons and target earth. I head back through the wormhole afterwards and wait 4 years.

No one on earth will suspect armageddon swooping towards them, since the light from Alpha Centauri showing the missiles hasn’t arrived yet.

Only when impact is imminent, 4 years later, will we be aware of our danger, and by then it’s too late.

The earth is destroyed and I rule earth, or what’s left of it.

I am sure there is an error in my logic or understanding somewhere, but it’s worth considering. Don’t you think?