That would be right when there is time to turn liveview off between two pics, which is not always the case.
I think the "powersaving" trick that you gave is better, because it should fit any scenario (i still have to try it but it sounds better because you don't have to have super powers of precision to switch LV off when there is , say, 1 second of idleness between two shots, or less than 1 second). Even with long exposure, one might not want to leave more than 1 second between two shots. That's why I think powersaving should be the best option. you don't have to think about it.
Moreover, you don't need to touch the camera with powersaving, so there is no risk of blurry picture due to a moving camera, which would kill a whole timelapse :-) (or at least the first shots)