Matrix is a protocol, Element is a Slack-like app on Matrix.

It sounds like you have issues with Element as a replacement for Signal, which I totally get, but I think it's worth distinguishing Element from Matrix.

Element being the only full-featured Matrix app hopefully won't always be the case and it's Matrix's express goal to change that. Element is a single reference implementation -- if it's successful it could spawn many others supporting different UIs and use-cases, which we're already seeing with Fluffychat sporting a Signal-like chat interface.

I'm pushing my family and friends to use Matrix because that's the direction I want the world to go (open protocol with many different clients and servers communicating), not because we're already there today.