Signal doesn't provide any method to backup and restore my chats, at least on iOS. Imo this is a very important feature, I have chat history going back for years and it's basically a rich media diary of my life. It happens occasionally that I want to look up stuff that has been shared a few years ago, especially photos. Is ownership over my own data really too much to ask? The possibility of losing my entire chat history scares me. I get that some people even consider it a feature, but without the ability to backup and restore messages it's not really a "replacement" for WhatsApp, it's merely an alternative with pros and (very big) cons.