It's only an service for a tiny subset of fundamentalists. While all dispensational premillenialists and members of the small Millerite sect are fundamentalists, not all fundamentalists are advocates of Millerism.
Miller was a date setter, but not an advocate of the traditional fundamentalist 'rapture'. He was waiting for the second coming which would have been very public and would have taken the righteous up to heaven before Armageddon/judgement.