I ran into a local store taking credit cards awhile back, no TLS, weird, so I go to the store owner in person. I explain the problem and he insists that can't be the case, he's mad at me. "See! It's got a lock on the website!"... on the homepage. I direct him to the store and now it says Not Secure.
That did more to explain the situation than my attempt at TLS and HTTPS and Certs. He was able to call his web guy and say "It says not secure, Jerry! Fix it".
It was such a simple addition to (at least in Firefox) use the words Not Secure that it's crazy no one thought of it before.