I agree. Metal cock rings are great and look as if they belong there. The problem is that they are difficult to size properly, especially if you suffer any kind of ED. I suffer from ED and I need a cock ring in order to generate an erection. Accordingly, I need one that is tighter than someone with similar girth but without ED. In other words, I do not use a cock ring to make my dick fatter, but use it to convert a semi into an erection. Therefore, I need a smaller inside diameter than the sizing chart suggests. Usually, the smallest inside diameter is 1.75”. In order to generate an erection, it turns out I need a 1.25” id. My EG is just under 5”.
Sometimes it takes two or more times before you get the right fit. I would recommend trying inexpensive hard rubber or brass cock rings until you get the best fit, then go for the good metal one to impress your date.