We've been waiting for Keybase, it doesn't mean we've been waiting with no solution meanwhile. We want to use Keybase because many of its other features.
You might be surprised, but for some people this feature can be life or death. My team has been actually waiting for Keybase to have this. We work in countries where some of us are regularly taken aside by the local police or armed forces and our phones are being checked to see if we have anything against the current government. We have to constantly make sure our communication has no traces. We'll be moving to Keybase very soon. Thank you for this!