Since this feature came out I haven't had to change my keying with Signal in over a year. To your point, for heavy use Signal users the flow is a bit arduous. I hope that Signal can offer a continuous backup option at some point so I can just have the app incrementally backup while I'm at home to my NAS. This would solve for both the problems of unforeseen mobile phone loss as well as the level of time it takes to migrate to a new phone.
In the interest of transparency I also use Keybase for things as well. The problem I ran into with Keybase my first go-round was I lost any ability to restore my account after I hadn't used it for about 9 months. That is mostly my fault for not having more bases covered, but had I had anything notable I would have wanted access to I would have lost it at that point. As an end user I don't feel that Keybase competes in the same manner as Signal. Since I'm an Android user Signal is 100% transparent to my normal use handling both SMS/MMS and Signal messaging. Keybase isn't a drop in replacement with that in mind. I realize this isn't the norm for iPhone users. Regardless, my question is: are many people using Keybase for messaging? About half my contact list uses Signal, yet I only have ever communicated with two people via Keybase.
In the interest of transparency I also use Keybase for things as well. The problem I ran into with Keybase my first go-round was I lost any ability to restore my account after I hadn't used it for about 9 months. That is mostly my fault for not having more bases covered, but had I had anything notable I would have wanted access to I would have lost it at that point. As an end user I don't feel that Keybase competes in the same manner as Signal. Since I'm an Android user Signal is 100% transparent to my normal use handling both SMS/MMS and Signal messaging. Keybase isn't a drop in replacement with that in mind. I realize this isn't the norm for iPhone users. Regardless, my question is: are many people using Keybase for messaging? About half my contact list uses Signal, yet I only have ever communicated with two people via Keybase.