Previous discussion of same topic: https://news.ycombinator.com/item?id=44053364

In short: Signal uses DRM to prevent Windows Recall (spyware) from capturing what's inside the app. It's similar to how Netflix prevents piracy.

That's an interesting use-case of web DRM.

There are other details in the article, for example about Recall forces users to use biometrics to then permit them to authenticate using a PIN code. That's an interesting observation.

and as plenty of people have noted, virtue signaling. As signal already saves one's entire chat history by default in an easily digestible db.

any security hole on windows that enables an attacker to get to the recall db, would just as easily enable them to get to the signal db.