It’s the fear of death and nothingness after it, which makes them believe in an afterlife. IMO.
It does remove some existential angst and for this reason some choose to believe in an after life. I do believe in an afterlife but I'm not 100% certain, more like 85-90% from what I have read, heard, and seen. Does it give meaning to my life? I would say yes to a degree, and it lessens my feeling of nihilism.
Hey we all may be part of a computer simulation that for what ever reason makes infinite amounts universes with infinite amounts of life, and in another state our consciousness exist after we die until it desires to reincarnate for what ever reason into our realm of consciousness.
I admit I kind of like the idea and find it interesting that so much research has been done.