The reasons to fork from a release standpoint provides a variant that is appealing for certain types of development. The numbers that it appeals will dictate, at least partially, its success/popularity.
The same applies from a maintenance perspective with the semver approach.
There's room for both or N forks really, as long as the users don't get burned out on too many options, which was the topic of a recent JavaScript MVC framework article (can't find it now).