In messaging contexts, it is well accepted that there may be times where you want to use disappearing messages, even despite the fact that your messenger (i.e. Signal) provides a secure, e2ee platform. Ultimately, this is because those messages, for whatever reason, are not worth keeping around past a certain point. And in many activist communities, messages or group chats could be used to correlate activity, attribute actions, or perform social network mapping. People then decide that the safest thing is to let those messages disappear to reduce the potential impact of a future "breach" of one participants' device.

Calendar events can be very sensitive, too. They can give times, dates, locations, and lists of people all attending a common event. Why do they need to stick around forever? Most users are never going to wonder "what meetings did I have on this day two years ago?". While at the moment, an enterprising privacy advocate could go back through their calendar and remove long-expired events, that current process would be tedious and time consuming. Why not just take a page from the messaging apps of the world, and allow calendar events to be defined with expiration times? When a user makes an event, they can say "it's at this place, at this time, and in 6 months, this event will delete itself from my calendar".