Richard Hays lists six reasons why the church needs apocalyptic eschatology (includes my own summary, paraphrase, and additions to his chief articles):
1. The church needs apocalyptic eschatology to carry Israel’s story forward. Without a future oriented hope one cannot affirm God’s faithfulness to Israel and God’s covenantal promises become unintelligible. Or even worse, a faithless God means we have fickle deity whom we cannot be sure abut. God intends to vindicate his peple (Deut 32:36) at the appointed time when the Redeemer comes to Zion (Isa 59:20). These promises find their proleptic fulfillment in Jesus Christ in the church as a prefiguration of the eschatological people of God, which is a sign in itself of the full divine embracing (proslēmpsis) of eschatological Israel.
2. The church needs apocalyptic eschatology for interpreting the cross as a saving event for the world. If we are to grasp the centrality of the cross, then we must see it as more than a propiatory sacrifice for the forgivnesss of the sins of individuals. The cross should be interpreted as an atoning even within a larger apocalyptic narrative where God destroys the powers of the old order and inaugurates the new creation (Gal 6:14-16).
3. The church needs apocalyptic eschatology for the gospel’s political critique of pagan culture. The biting edge to Christian eschatology is that Jesus is the Lord to whom every leader and government will one day bow (Phil 2:9-11). Christian apocalypticism reminds us that Caesar’s power (in whatever form it takes) might claim to be totalitarian, but in fact it is transient. Christian loyalty to the Lord means resistance to the power, politics, and pleasures of the world around us. If we train our eyes on the ultimate reversal of fortunes then we will never become accommodated or complacent with the status quo in an injust world.
4. The church needs apocalyptic eschatology to resist ecclesial complacency and triumphalism. The looming reality of a final judgment – a judgment that begins with the church – strikes a chord because it prevents the church from having grandiose concepts of its own importance (see 2 Cor 5:11–6:2). The church is a provisional servant of God, a life boat between shipwreck and salvage, and so must avoid becoming fat, sleepy, or abusive.
5. The church needs apocalyptic eschatology in order to affirm the body. Apocalyptic eschatology is in one sense dualistic between certain temporal and spatial entities (e.g., heaven vs. earth, future vs. present, etc.). However, that dualism is never annunciated as a radical rejection of the material world in toto. For apocalyptic eschatology looks forward the the Creator’s redemption and renewal of the created order and his refusal to abandon it to decay. God redeemes what he creates. That is why Christians look forward to the resurrection of the flesh and not to the immortality of the soul (1 Cor 15:35-58).
6. The church needs apocalyptic eschatology to ground its mission. The resurrection and ascension of Jesus was a sign that Israel’s restoration was indeed at hand (Acts 1:11). Yet it was also a call to engage in witness to the expanding kingdom. That witnessing inevitably brings the witnesses into conflict with a world hostile to the message of the lordship of Jesus Christ. The Holy Spirit empowers the church and forms the community as a missional organism that works out God’s purposes for redemption and judgment. Without this endtime perspective the content and urgency of the Christian mission is greatly retarded.
7. The church needs apocalyptic eschatology to speak with integrity about suffering and death. Those armed with an apocalyptic eschatology need not live in denial of the sufferings of this age and the groaning that accompany it. Cynicism nor despair takes over Christians because they know that their telos is the resurrection of their body assured by the resurrection of Jesus’ body. Christians therefore know how to grieve with hope in the face of the horror of death knowing that every tear will one day be wiped away their eyes in the new creation.
 Richard B. Hays, “‘Why Do You Stand Looking Up Toward Heaven?’ New Testament Eschatology at the Turn of the Millennium,” in Theology at the Turn of the Millennium, eds. L.G. Jones and J.J. Buckley (Oxford: Blackwell, 2001), 113-33.