The stakes are FAR higher. Live a faulty life now, and your "afterlife" may be an eternity of torment. This is a humongous millstone around a person's neck.
If I may interject, one could also consider "the opinion of posterity" or "the future of humanity" to be a sufficent reason to take certain actions that affect your existence beyond your lifespan, so to speak.
In any event, I really can't see the problem with guilt. It allows us to maintain our ethics, which are in turn necessary to keep us from destroying everything around us. If you think that we destroy now, imagine a world where there was no guilt, no remorse. The destruction that is attributed to guilt is not from guilt and remorse, but from the failure of guilt to operate evenly. Release people from responsibility and contemplation of the results of their actions and you harm humanity more than you could ever dream of.
Do you jump for joy because you are released from obligations that you feel to be onerous and useless? What if everyone shed their onerous obligations when they felt that they could not comprehend the ends to which they were pointed, or even disputed the direction they were taking? Responsibilities are frequently annoying and difficult to comprehend without some idea of what the result of those actions will be.
A concept of the Inferno or Heaven might seem childish and superstitious to some, but to a population that lives it's life doing things that they'd rather not do, it's a blessing. It's a goal that can be visualized, or something to be avoided. Heaven is most likely not a place where you are issued a harp and Hell is probably not literally on fire, but those images do stand in for the far more complex realities of what happens to you and all of us when we make good decisions and poor ones. In that way, heaven is likely infinitely better than you'd imagine and Hell infinitely worse, not because they are places to go, but because they are condition we reach or even create through our action or inaction.
Hell is only a burden for people who'd rather not do the things required to avoid ending up in that state. Nevertheless, denial of Hell as a place or concept does not affect the reality of a situation. Bad decisions make for bad ends, and denying the effect of a cause does not make the effect any less real simply because you don't like it. Hell, whatever it is, would not cease to exist if you don't believe in it and given the power of belief, I often wonder if it that very power that is what makes such states a reality.