I was thinking about WhatsApp, because it's an awesome and controversial story. When comparing to Damus (ignoring differences in protocol), there difference with WhatsApp is that it is a client that doesn't allow users to send and receive messages to other clients of the same protocol. This gave it extra power in having first mover advantage, but it makes it inoperable.
I think next to the properties you name there is also the potential of allowing for a low threshold experience because Nostr only requires one verification that is then inter-operable over the whole width of the protocol.