this manga is really interesting to think about
because there is actually some truth to all of this
there is that saying "that the human nervous system cannot tell the difference between real and imagined experiences" and this is just what is happening here and that also happens in real life
"imaginative" experience affects your existence to quite a big extent
though it still seems to have its limitations there are some study that says that the brain can actually differentiate it by using a "reality threshold" and that could limit the changes caused by the imagination or dreams
another limitation is that the majority of people cant really visualize things well nor control their dreams