See... Part I understand because some few do butt into something you're doing with someone, and kinda ruins the flow (unless actually invited to do it, then that's something different.) Then again, mentioned by Zenta, you can use content filters and privacy settings to fix this.

At the same time, people just prefer to keep things private in messenger/ conversations, as well as it helps keep things more organized and you don't lose it because of the flucts of notifications one can get.

There's also the fact people like having discussions in their roleplays over some sudden photo comment roleplay.