I wonder if their acquisition of keybase has been done long enough for it to have been helpful here.
Zoom acquires Keybase: https://news.ycombinator.com/item?id=23102430
Zoom acquires Keybase: https://news.ycombinator.com/item?id=23102430
There are secondary benefits, the acquisition did bring some probably-helpful talent around encryption/infosec, but as you said the rollout seems really fast vs acquisition time for a product that size.