There is no video calling, but I already have other solutions that I use for that. Keybase is end-to-end encrypted as mentioned in the other comment, has good multi-platform support, and is free. The fact that the user can revoke a device if it is compromised is excellent. I also have intentions for using it as a secure SSO ID across company applications using the API(https://keybase.io/docs/api/1.0/intro). (Basically replacing how some companies use Active Directory)

For me the secure identity and communication part of Keybase is a critical base layer that no one else really gets right. I can have a new hire create a Keybase account and use that to securely exchange documents (e.g. w-4 allocation, health insurance, etc.) two weeks before they are even part of the company.

The only long-term downside to Keybase for me is it is a centralized cloud service run by a single company and the application is not open source. What I really want is a decentralized open source version of Keybase that's operated as a global network that lots of companies/individuals ran nodes for and you paid for your use of the network. That way I'd be more certain that it will be around in 10 years time.