It opens up creative possibilities by ignoring creative intent. So, it kind of ignores what the authors are trying to communicate.
Which is fine, as individuals can put their own interpretation on a work of fiction. Just not my preferred method of engaging a work.
Yes and no. To hear Orci and Co tell it, every time travel episode in Trek history created an alternate universe/timeline. Counting the shows and movies, that's over 50. Not including the unknown, possibly infinite, number of alternate quantum realities that pop up from all other causes.
That's them saying this, not me. Orci himself said that in a manner of speaking there is no "prime" timeline at all really, even while insisting that the elder Spock is from the 24 th century continuity last seen in Nemesis.
If everything that can happen, does happen in alternate quantum realities and every time travel case (ST IV, ST FC, etc) creates alternate timelines who knows which universe/timeline/quantum reality elder Spock is from?