I think a reasonable compromise would be to just insist on some type of federation with other systems. These days that means XMPP federation. Then the option of

I think a reasonable compromise would be to just insist on some type of federation with other systems. These days that means XMPP federation. Then the option of OTR for privacy and you are good to go. You can provide all the fancy features you want between your clients, but those clients will also have the feature of being able to communicate with people not using your app/program. Perhaps the combination of federation and OTA can be given an impressive sounding name, a nice logo and a foundation (everything needs a foundation). Then the name/logo can show up on feature lists. People love features...