Something that isn't really discussed much: A particular protocol/network/provider/client app gets only one shot to be accepted by your contacts. There are also a very limited number of total attempts. So if you're browsing https://www.privacytools.io/software/real-time-communication/ and decide to try to get your contacts to use a particular messaging service / messenger app, it has to work reliably, without freaky, scary bugs, or complicated work-arounds.