Giffer's primary focus is creating animated gifs instead of videos. As such, there is currently no option to output video from gifs. You can save animated gifs to your photo album, just not videos... yet. One unfortunate side-effect of saving gifs to the camera roll is that Apple's "Photos" app cannot play back the animation. See here for a workaround.
I do hope to add support for gif-to-video conversion in the future, but there are several other features taking priority at the moment. In the meantime, if you'd like to vote for this feature please do!