You are probably right but I wouldn't discount the keybase server/client IP and user base completely. If Zoom could use keybase for identity verification and adding participants to a call via social graph connections of everyone on the call that could radically improve the UX of onboarding and securing a meeting to only approved participants.

It's possible, though I think it's optimistic. Nobody really has a problem with Zoom's UX as it is now. The only people complaining about Zoom are us techies who know about the security issues. So my guess is they're just gonna quietly work on the security stuff in the background with this new team, and leave the UX largely as-is.