Why is this feature bad?

As someone who develops apps for confidential conversations, making it harder for people to screenshot the confidential stuff is a feature the sending party wants, that is why they send in your app as opposed to others. It doesn’t make things impossible, just hard enough that 95% of people won’t bother to take a copy.

Same for example with disappearing audio messages on whatsapp

What I don’t like is the app being informed that I took a screenshot. The OS can hide things in screenshots without this.