The more we can bring an image of that person and a feeling for that person into my present mind, then maybe I can feel that empathy that will make me make better choices now on behalf of that person. That's exactly the idea. The more we can make that future self more vivid, what we're really doing is taking the fiction of our future selves and making it more real.
It may sound strange, but if you can learn to treat your future self like someone you really care about, then you'll be more likely to make satisfying, rewarding, and ethical long-term decisions.