Ask HN: Why don't personal chatting apps have a disable option?

I have used many apps (telegram, whatsapp, hangouts) and have found that none of them provide any disabling feature, where one can disable the app for a certain time period to avoid any distractions and even addictions. Ideally, anyone contacting that person during this period should be notified that the user has disabled chatting temporarily.

This is a very useful feature from the point of view of the users, yet it is not commonly available. Why do you think it is so? Are there any apps that have such a feature?