I have played with Matrix on several occasions. I think one of the big promises was E2E encryption and as those who have worked in the area know it's not an easiy problem to solve. I have accounts on more than 1 homeserver. I have various keys in my password manager which I don't necessarily understand how they are used. I have old messages that I cannot decrypt, despite being sure that I have never lost any keys.
In summary: In my experience Matrix has not been an easy experience even for a user of gpg.
Here I am not asking how is this made secure and usable. I am just asking is this usable for anybody who does not even know what a homeserver is, would never understand what a key or fingerprint is and has no account yet?