Not only are they actually very closely linked, in that Element operates matrix.org, but to a new user (told to try Matrix -- what is this Element thing?) there's no difference.
I onboarded a family member onto my Matrix server with FluffyChat as the client. This person is a power user, fairly technical, yet still refers to the chat as "FluffyChat" and although I've explained several times that choosing FluffyChat was maybe a mistake and they should use Element, it never seems to really click that multiple clients are possible.
And really, they aren't possible. They have different subsets of features.
If you want to see a trash can fire, just try to follow the discussion for adding custom emoji to Matrix: https://github.com/matrix-org/matrix-spec-proposals/pull/195...
it's been going on for years. It's a feature the competitors have had for half a decade, as long as this discussion has been ongoing. I've been watching this issue for half a decade thinking "surely they'll decide on something" but mostly all I've been convinced of is this: Matrix is design by committee in all of the worst aspects and at every level of design. If anything gets done at all, it's a convoluted mess, and it's a miracle that it even happens.
I wish community software developers would focus their attention.. somewhere else.