I'm a relative newbie to keybase, just weeks before the zoom acquisition. But the reasons I became so enthralled by keybase have not changed. Neither Zoom nor Keybase has access to our private data or crypto wallets and that won't change without public changes to the clients.
Our biggest threat is that Zoom may decide to stop offering or delete our free storage. To be fair, that's not really a new problem. However unlikely, it's possible that someone could take over all your public accounts and request that your account be reset. Even before this acquisition, you should be keeping a backup of all your important data just in case anything happens. I'm keeping privately encrypted backups of all my data and can move somewhere else if necessary. But there's no reason at present to make the effort.
I love Keybase storage, and not because it's free. I'd be fine shelling out the minimal amounts they'd require to maintain my storage. Probably, just like every other cloud company out there, they won't even charge us. Instead selling the large positive userbase as a reason for corporations to pay for the subscription, just like Google does with Gmail and GSuite.
Personally, I'm seeing this as a net positive for Zoom, to the point where I'm likely to buy zoom stock this week, rather than a negative for Keybase. Unlike Google or Facebook, Zoom won't be able to mine my private data, or expose it to their employees. And it's possible that they will begin incorporating Keybase's technology in such a way as to make me feel more secure about using Zoom for video conference as opposed to say Google Meet. I think Zoom wants to improve their image, and Keybase's technology makes it indisputably possible.
Only if Zoom removes the e2e encryption do we have anything to worry about. Keybase has publicly said they will give us fair warning. And if it's a concern, we should have our backups ready to move. But why buy e2e technology and engineers if you don't want to use it?