Because of what it teaches us about Jesus (chapter 1).
"Revelation is not a puzzle or a horoscope. Above all, Revelation, thoughout, is the 'revelation of Jesus Christ' (1:1). We learn much about Jesus from the Gospels, as we watch his life, his actions and teaching, and above all his death and resurrection on earth. But we also need to absorb the supernatural vision that Revelation 1:12ff gives us, that makes John fall at his feet as though dead (v17).
We don't need to understand every detail, but we do need to let that dazzling holy purity soak deep into our imaginations. Those eyes like blazing fire, that we encounter either in surrender or in judgement; those feet burning as he walks the earth, amid his churchs; that sword from his mouth that is the piercing Word of God.... Here is an overwhelming force of life that leaves the Apostle (who lent back so easily against this same Christ's shoulder at the Last Supper) devastated on the ground. Our Christianity is incomplete if we have never understood why.
And then that Christ places his right hand on John (v17; imagine how that would feel) and he says: 'Do not be afraid.' He does not waste these words on those who do not need them. And what he adds (v18), we can turn straight into acts of adoration...
...the vision of Christ's glory is what equips John to hear God's Word for his culture. But this is only the beginning... amid all the puzzling symbols, we need to keep anchored (and responsive) to that."
Eleven reasons to reread Revelation
in Gateways to God, Pete Lowman.