One lethal consequence of the mainstream modern assumption that death is annihilation, is that it renders this mortal life merely palliative.
Because life is assumed to end in nothingness, mortal existence cannot be more than palliative: i.e. a series of temporary attempts to avoid or alleviate suffering... and maybe attain some temporary pleasures.
This nihilism is what seems like ordinary "common sense" to the modern Western mind, and has done for several generations.
It is the great benefit of assuming a continuation of life beyond this mortal life, that it makes it possible to have a positive purpose - because there is the prospect of carrying-forward something of whatever we have done in this life.
This benefit of a potentially purposive life, may derive from a variety of convictions about the nature of life-beyond-life (e.g. resurrection, reincarnation, forms of paradise etc).
The point is that a continuation of our life after death is what makes purpose possible; whereas the contrary belief that we are extinguished at death, makes any subjective feeling of life-purpose into just a futile delusion.
Given that so many people in The West (especially among the higher and leadership classes) apparently regard their own death as absolute the end of themselves, and anything else as mere wishful thinking -- many things about the experienced futility and evil of life in Western modernity become understandable - indeed inevitable.