Signal has a lot of things going for it Matrix doesn’t have… more convenient, simpler, easier to use, more focus on privacy, better calling. Matrix does some things Signal does, but they have different feature sets really. Matrix being free software, unfortunately, doesn’t matter to most people. Matrix also arguably isn’t really about security and privacy. It’s more of a universal chat platform, so they don’t compete directly.
The fact the Matrix is usually marketed as a platform for secure and private communications is somewhat difficult to understand.
Holy cow