A human doesn't need to understand the proof, they just have to understand why the proof is a proof.
Yes, it was still proven. If I don't speak English but come up with a proof, I can't communicate the proof, but I have still proven (ie created proof) it.
To what extent is the proof of Fermat's Last Theorem "incomprehensible to humans" because only like a dozen people on the planet could truly understand it - I don't know.
The point of new proofs is really to learn new things about mathematics, and I'm sure we would learn something from a proof of Goldbach's conjecture.
Finally if it's not peer reviewed then its not a real proof eh.
Thinking back to Wiles' proof of FLT, it took the community several years of intense work just to verify/converge on the correct result. And that proof is ~130 pages.
So, what if the computer produced a provably correct, 4000-page proof of the Goldbach conjecture?