Although this is intriguing, it's a thing that will be impossible to test for centuries. This offers another account of creation, but it smacks to me as unprovable as saying God did it. An analogy I think that applies to this is like saying money was created when the first coin fell on a caveman's lap.
I understand and accept the spontaneous existence (and annihilation) of subatomic particles, but today's particles are appearing/disappearing (in theory) in "established" four-dimensional space-time--something that wasn't (hypothetically) present prior to or at the Big Bang.
I agree with Hawking that God isn't needed to explain creation, but spontaneous creation is as much of a stretch. Both require pre-existence of some agent or condition for creation to occur, and I think that house is being built on an insurmountable paradox.