One may wonder what the point of adding these is to an e2e messaging app, but I would contend that you don't want your messaging app to get into the same predic

One may wonder what the point of adding these is to an e2e messaging app, but I would contend that you don't want your messaging app to get into the same predicament as PGP where mere use of the app is considered suspicious. You would also prefer it if your friends used this app so that you could communicate with them and not have to spend forever convincing them. I am a Signal user, but as e2e crypto has moved into more mainstream services such as WhatsApp, and even Facebook's Messenger I've stopped trying to convince friends to install Signal since it's easier to just initiate private chats in these popular messengers.