The branch predictor can select a random branch, so it doesn't even need to actually predict anything. It should use quantum noise so that it has chance of selecting different branches in different copies of the universe. There is noting to compute, quantum or otherwise.

The bomb to destroy the universe will take care of all universes where it made wrong predictions, so that is where we should concentrate our development resources.

It has more utility than just branch prediction. Imagine the bomb going off automatically whenever there starts a war.

Any copy of the universe that starts a war is automatically eliminated and this guarantees that you, as an observer, will never observe any wars.