Odell and Derek don't run Zap.stream, also the streams are both conected to Nostr and at least zap.stream is open source, not sure about nests but I assume it is.

If you login via an extension your keys are fine to the extent the extension keeps them that way. And Npub logins are great because you don’t have give up all your personal information to use the service.

Nostr login and authentication, Nostr chat, Nostr reactions, nostr zaps, Nostr presence, Nostr events. The video and audio are not over Nostr. Everything that can be is a Nostr event and transmitted over relays.

They are apps that not only support logging in with a nostr extension, but also publisjng various nostr event kinds to share the relevant information.

Corny Chat integrates nostr, and provides a summary of the event kinds it uses here

https://cornychat.com/datatypes

These apps are all effectively centralized in operation, but provide source code if anyone wants to run their own instance

I wanna know too… not sure if I wanna invest my time in building a community on these or just stick to youtube or twitch