Spider-Man: Far From Home - What Does The Multiverse Mean For MCU?
5. Alt-Versions Of Characters
That idea of the Joker movie having a different version of the character to the one in the DCEU (Joaquin Phoenix as opposed to Jared Leto) is quite pertinent to the Marvel Cinematic Multiverse is another way too. Not only is the door open for new standalone stories, but it's also very much open for alternate versions of already existing characters.
Endgame hints at this itself, by having the Loki of 2012 steal the Tesseract and disappear. He therefore exists in a different reality, and since he's getting a Disney Plus series, we can expect the TV show to follow that Loki in that universe. Introducing the multiverse in Far From Home backs up that idea.
It works for a number of characters too. The animated 'What If' series, which will include a story where Peggy Carter became Captain America, and Steve Rogers became Iron Man, was expected to be completely separate. Now it can be part of the multiverse, and they can tell numerous stories where characters are different (again, this is something DC have already had success with, this time on TV with the Arrowverse). It might be they want to introduce a new Iron Man, a different version of Ghost Rider, or whatever else they dream up. The multiverse can allow for that.