+rehtorbF03 Well, we can at least rationally think about what the consequences of this interpretation would be.
As I said under one video which was criticizing the MWI:
"Very interesting topic and all the reasons given against the MW-interpretation like the problem of deriving the born rule or the problem of observers are very meaningful and logical. The basic idea behind it was that after the wave function of a particle collapsed, then ,what happens to the other properties and where are they. So, they took the location as a fixed and defined property and I guess that was maybe one mistake.
There are also other theories with many worlds not derived from quantum mechanical reasons but more like the idea of parallel universes in higher dimensions etc. . Most of them should give us a reason why our universe is so "perfect" without the existence of god. Well, they have also good arguments with a high probability etc. but I always ask me how this multiverse structure can be sustaining,because when our universe gives us so many problems with the complexity and the perfection,then the multiverse must be much more complex and give us much more problems than now. And they also fail in other aspects. If for example the number of the parallel universes is infinite or very large,then it should have a 100 % probability for at least one of the universes having developed an advanced civilization inside it which should have the ability of creating wormholes and already have visited us.
Professor Deutsch says in his theory that in the future computer power will increase rapidly and that time travel would be possible in this virtual reality which sounds possible but I have asked me that if the entire universe is virtual,then time travel should be possible there."
I am not supporting the theory but it's implications on the way how we deal with the Quantum theory are well formulated and thought out.
As one of the criticizers of the MWI, physicist Adrian Kent, wrote a book against it, he says:
"I also point out some (I think insuperable) problems with recent attempts to describe how many-worlds theories can be confirmed or disconfirmed by evidence. And I explain why the attempt to reinterpret the Born weights as some form of "caring measure" in Everettian quantum theory aren't rationally compelling."
or
"When (...) many worlds interpretation is spelled out and analysed, it's problems turn out to be sufficiently serious to cause most physicists to look elsewhere."
The Quantum MWI does not make any predictions and it is not a theory from which we get sufficient and beneficial results. But at least, it could be one possible option and we should take the possibility into account.
I agree that getting entire worlds after each collapse is not very efficient, but efficiency does not directly mean it is wrong or right.