That’s a very bold statement from an app that still requires a phone number using a broken protocol (gsm) to “verify” your identity and authenticate it, sim swap attacks can be carried out by kids these days. Also, don’t expect privacy when you are using a proprietary OS like iOS or one full of Google services that also have proprietary firmware drivers, they (the adversaries) don’t need to even decrypt these “privacy apps” when it’s easier to access the backdoor-ed OS or hardware, but enjoy the illusion in the meantime.
Not to mention that half of your comment is non-issues.
that said I stopped using Signal years ago because of basic deliverability being less reliable than SMS.. I switched back to SMS so I could communicate reliably with a loved one during an emergency when Signal randomly stopped letting me respond to messages, and I won't pay the social cost twice of trying to convince contacts to use it after having to abandon the service when I really needed it.
Actually between Element and Signal and the differences between their usability as advertised versus the reality of using them with non-technical users, I've used up all of my social capital for convincing people to use "better" networks and mostly just use SMS/RCS now.