The current convention of describing those who die as having passed away provides a less confronting way of dealing with death.
Christians have seemingly lost the biblical distinction by which we instead could simply say that believers who die have fallen asleep.
Perhaps through a desire to avoid any impression of the doctrine of soul sleep, or to avoid having to articulate the distinction that we believe that only Christians will wake to everlasting life we use a familiar and largely meaningless expression.
This is from an article called Sleepers Awake by Todd Brewer. It appears in The Mockingbird issue 21, themed on Sleep. It was also posted on their website.
Brewer looks at how Jesus and Paul refer to death in various contexts in the New Testament, what those references mean for Christians when they come to faith in Jesus, and when the earthly lives of those disciples end. To sleep in Christ will be to wake in glory.
…when Paul uses the literal language of death for believers, he seems to mean it more abstractly. Believers “have died to the law” (Rom 7:4), or they are living in the world as though they are dead, yet living (2 Cor 6:9). Describing his life as an apostle, Paul declared that he dies daily (1 Cor 15:31). He uses the literal language of death to describe the death of Christians before their hearts stop beating and their neurons stop firing. Paul believes that death must be experienced before death actually arrives. But it’s not some Stoic acceptance of death’s inevitability — that one must “come to terms” with Thanatos before he comes knocking on your door. No, the kind of death Paul has in mind is the death of the old self, crucified with Jesus, so that one may also share in the life of the risen Jesus (cf. Rom 6:5). Or as Paul succinctly declared, “I have been crucified with Christ. It is no longer I who lives, but Christ who lives in me” (Gal 2:20).
This “death before death” then informs how Paul writes of the physical demise of believers. In these cases, Paul almost exclusively uses the metaphor of sleep. He says that Jesus’ earliest followers have now fallen asleep (1 Cor 15:6); a widow is free to remarry after her husband has fallen asleep (1 Cor 7:39); and some have fallen asleep after eating the eucharist in an unworthy manner (1 Cor 11:30). Writing of sleep in such mundane contexts suggests that the metaphor was commonplace for Paul, his go-to way of talking about the death of Christians.
But why is “sleep” Paul’s preferred language here? His usage elsewhere arises precisely within debates over the resurrection, explaining how it’s possible that death is defeated and that Christians can still die. When members of the Thessalonian church begin to die, they urgently write to Paul, worried that these individuals will miss the boat when Jesus returns. Paul assures them that God will bring with him those who have fallen asleep. They should not grieve over those who have fallen asleep, like the Gentiles, who have no hope (1 Thes 4:13-14).