As a writer of fiction, I find the concept of the Multiverse no end handy!

As to any 'Real Life' applications, it's in the realm of "how could it possibly matter?". Don't scientists have enough to do curing disease, feeding people, reversing or at least ameliorating climate change?

I submit that money spent on this kind of study, which has no practical benefits and probably never will have, would be better redirected toward finding clean new sources of energy.

The quest to understand the Universe has a fundamental flaw, in that our understanding will always be limited by our senses and the structure of our minds. Thus everything is, in a sense, subjective because we can only interpret observed phenomena within the constraints of our brains and minds. It is not the limits of our intelligence that precludes us from finding objective reality, but the fact of our intelligence. That intelligence forces us to interpret what we see and thus renders it subjective. It's not wrong, it's just how it is.