This loses something important about Keybase sigchains: on Keybase, a sigchain represents an identity and not a single key, which makes it possible to add separate keys for different devices and to seamlessly replace and revoke keys over time. (Non-key-specific sigchains let the Keybase client do interesting things like automatically re-encrypting shared data when someone revokes an old key.)
Tying sigchains to keys seems limiting, and I'm curious if there's a reason for it. Otherwise, I like this a bunch.
Indeed, in a perfect UX you'd never manipulate keys, always identities; that gives keys less importance and allow them to be rotated in a period that's closer to 10 weeks than 10 years. Also, exchanges are done with identities, not keys.
Tying sigchains to keys seems limiting, and I'm curious if there's a reason for it. Otherwise, I like this a bunch.