get everyone to message you on that new account, reverify all of your devices, resign everyone you communicate with, etc. It's a nightmare. Everyone just uses the ever-bloated matrix.org home server anyway. This isn't all to say that I hate Matrix, I use it, I'm just saying don't baselessly attempt to bring down Signal in order to try to get people to use Matrix, the benefits are few and far between and for the general public Matrix is *not* the way to go.
3/3