There is no reason to project the promise of this verse into the (distant) future, namely, when the Lord returns. The church already functions as a pillar of the truth (1 Timothy 3:15). The community living around the saints already can see that those who conquer are God’s people, have their citizenship in the New Jerusalem, and have their status is only because of the Lord’s gracious work.
12 The one who conquers, I will make him a pillar in the temple of my God. Never shall he go out of it, and I will write on him the name of my God, and the name of the city of my God, the new Jerusalem, which comes down from my God out of heaven, and my own new name.