For me, bothering about what will happen after death is a waste of time for two reasons:
1. There is nothing you can do about it and
2. You probably won't know whatever is going on.
Points 1 and 2 are both true. However, whilst belief in life-after-death has zero meaning for those who are already dead, it has a great deal of meaning for the living.
Yes, it can act as a powerful driver of behaviour, often in a detrimental way as in the example on a previous page about soldiers or (can't believe I'm agreeing with BADecker here) suicide bombers.
But it can also act as an important crutch to those who for whatever reason need that belief in an afterlife to help and support them in their actual here-and-now life. Death rituals such as funerals are vitally important to surviving friends and relatives as a means of formally acknowledging death and the transition to whatever is afterwards. It can help bereaved people to believe that their loved one has now departed their mortal body and is now a soul ascending to heaven, rather than just decomposing gradually in the dirt.
Personally I am an atheist and have zero belief in life after death. But I will accept that the belief itself can be a source of good.