This makes it easier to maintain multiple Tab workspaces involving the same files. For example, in one workspace you want a class and its spec, and in another tab you want to see that class in context with another collaborator. This allows you to open the window multiple times.
We are purposefully including an older version of snipMate (0.84) from mikefarmer's repo so that it works with the long list of snippets available from the scrooloose/snippets collection. The current mainline snipMate seems to be no longer compatible with those snippets, but the scrooloose collection is still the best one to use.