If there's no continuity then... what's the point exactly? Reset buttons are my ultimate pet peeve when it comes to narrative devices. It just makes it harder to care or be engaged.
There's continuity between shows, but it's an illusion, and requires HUGE amounts of willing suspension of disbelief to hold together.
Yeah, it's cool to think Admiral Janeway knew Picard who knew Sisko who met Kirk... but then, how did Kirk get from the rim of the galaxy to Earth and then to the centre (twice if you include the cartoons), when Voyager's galaxy-spanning journey on the fastest ship in Starfleet should have taken 75 years? Why does Deep Space Nine ignore all the cool things hand phasers can do? You have to kind of pretend all the other shows happened differently in the context of whichever one you're currently watching, otherwise episodes like "The Seige of AR-558" look incredibly dumb.
Janeway knew Picard who knew Sisko who knew Dax who knew McCoy who knew Spock who knew nuKirk. So IMO it's the same continuity if not the same very blurry history.
So, JJ, make me change my mind. But don't insult my intelligence by calling it a multiuniverse. Just say, these stories happened when Kirk was young. That, I may be able to accept.
Multiverse is just a sci-fi way of calling it a "what if...?" story. What if a crazy Romulan showed up on the day of Kirk's birth and started raising hell? How would Spock cope if his planet were destroyed and his mother killed right in front of him? Now we're gonna see the aftermath of all that. Old characters, new situations and no need to hit a reset button at the end to set up the old show.