3. It also establishes a connection to the DC Cinematic Universe

Here is the real hook of the multiverse; it doesn’t just need to be limited to TV. If the big screen adaptations of Batman, Superman and even the Flash remain successful then the ability to crossover to alternative worlds means we could see Henry Cavill’s Superman appear in Legends Of Tomorrow or Ben Affleck’s Batman arrive to help Oliver Queen in Arrow.

It would have to in a careful, well-crafted manner, but it would be a great way for cameos and/or special crossovers. Ezra Miller’s Barry Allen meeting Grant Gustin’s Barry Allen; it could happen and in the same manner that Marvel‘s TV shows have a connection to the likes of Iron Man, Thor, and even Guardians Of The Galaxy, the same could theoretically work for DC. A multiverse connection between the alternate worlds of the big and small screen would be a massive coup for DC.