Every night we create worlds of emotional experience starting from the images which are internal and subjective, until we break through to the astral realities from which we can explore and develop in our spiritual relationships. Usually we must increase our capacities for lucidity, including the "aha! I'm here!" awareness for self-presence, the fully felt and appreciated ranges of our emotions and senses, and the will to make reflective decisions, in order to bring back our astral frontiers sensibly. When's the last time you had a positively cathartic dream, in which you cried so hard for something you loved that you woke up amazed? Or a rendezvous dream, in which you met someone so real and appealing that to even remember that it happened is to feel your body flare with yearning and desire? Most people remember only vague fear and confusion from their night dreams.
Actually, everyone is stumbling into the astral fringes on a regular basis, but few do much more than just mumble about, grab at some enticing images and run from some others, then come back empty handed and forgetful. A nice and natural progression seems to be available diurnally in the movement from (1) our internal headspace dreams, which tend to be chaotic, associative, purgative, and populated by our personal memories (some older familiar and recurring, some just recently formed and still settling in our impressions), to (2) increasingly self-controlled and narratively ordered lucid dream environments, still personally generated but with some opportunities for higher intelligences to enter, guide, and stabilize the events around us for our benefits, and then, once we've cleared our emotional baggage for the evening, (3) popping full force into the real spiritual worlds which are characterized by our focussed interactions with genuine others with whom we can feel much love and affection, and where we can have impressive adventures through sequentially visited, memorable, instructive, and extremely satisfying sensate environments. A potential step (4) can be when you wake up back into your life again, but now with new intentions as a newly decided you. You might even one day choose to wake up into that recurring dream of an alternate life that you've been having bits of, because it could be useful to fully and consciously drive in that part of you for a while... after all, whoever said you had to keep waking up into the same life, or that you ever exactly do? But you're adjusting only as much as you're ready to of course, for you are in charge.
So, amazing possibilities aside, I can certainly understand why people who only occasionally remember their dreams of stage 1 can't understand what all the fuss of dream recall is about. Stage 1 is where the nightmares happen, the anxiety releasers, and you can feel really lousy and low self-esteeming just trying to force yourself to write down for later decoding a stage 1 dream memory. But that is part of the natural barrier system of the wounded psyche, for only when you are self-accepting and practical enough to work through your stage 1 dream self-healings (try to associate to when else in your life you feel the way you did in the dream, to see what issue the symbolic environment is replaying, because neat as they are there are no valid absolute symbol dictionaries), only then will you allow yourself to enter into stages 2 and 3, where just a few moments in these spaces can exhilirate, inspire, and guide you for days, weeks, or even years.
The cheaper incentive to astral study should simply be that when you die, you are going to be entering the astral realms forever, so unless you want to find yourself in endless nightmares and chaotic dreams from which you can't wake up (this is sadly how many discarnate spirits feel), you will want to develop your higher dreaming savvy now, while you still have a physical body "homebase" to return to for comfort and timeouts.
It's a curious concept, eh? That waking life is actually meant to be the rest period from the true daily work of dreaming responsibilities. But it's true, because the physical world has consensus momentum properties which make it a good sanctuary to escape to when we've become overwhelmed with what's really going on inside of ourselves. The higher we go in realities, the less "time" and "space" we have to put off facing the consequences of our decisions and moods. Heaven is just the state of being in which we always know and desire the best for everyone concerned, and thus we welcome the best to happen instantly in front of our eyes, because God is the one who can always say yes to love.
Every thought we think does manifest somewhere - but we have to be quite guileless and self-understanding to stand to live in our own state of instant and immediate manifesting. That's why the wicked throw themselves out of heaven, God never does - it's the same as when we scream desparately "I've got to wake up now!" when we find ourselves inside a nightmare in which we've let out some of our baser drives only to lose control when they come attacking us. Judge not lest ye be judged! So we keep testing ourselves. Am I ready yet? That's what will make a nightmare... or a real dream of heaven.