Your dreams and imagination evolved as a view into another universe. As with the current beliefs, you cannot decipher technical information -- no words in books, no details of how devices work, so even if you can describe things you see from another place, you could not reproduce a working version.
Now how do you convince others that the things your are seeing are really happening without being labeled insane? And how could you use this information to benefit yourself or others? Take a peek into the multiverse to see how other versions of yourself have solved these problems...
If you can't functionally use any information from the other universe or vice versa, then what's the difference between a real universe or a fake one.
Honestly it comes down to a similar question about whether or not you are living in the Matrix. If you can't change or control anything, then it doesn't make a difference. But if you can find a way to hack the system, what could you do with it? I'm enjoying seeing the different theories that everyone has.