Except things like quantum computers. It's almost like those worlds do exist and that we can even use their transistors to parallel process stuff.
Well that is definitely a fun thing to say. It doesn't seem to be consistent with what is currently thought about quantum computers and Many Worlds, though.
Your link to the wikipedia article on the MWI does not clarify your objection to the statement made above.
How many universes "branch off" from a "quantum event", and in how many of them is the cat dead vs alive, and what about non-50/50 scenarios, and please answer so that a physics dummy can maybe kind of understand?
(Is it just 1 with the live cat and 1 with the dead one?)