My e-ring is pretty unique, and also didn't come with a wedding band. The thought of adding a band makes my heart hurt, it's so beautiful as it is. The sentimental aspect of a wedding band doesn't matter too much to me. In addition, if FI only gets one ring, why do I get two? That's silly to me. When I get married, I plan on just having FI put my e-ring back on my finger. I want my one ring to do double time and be my wedding ring when the time comes.
Most people I tell IRL is super judgmental about it. Nobody really has a good reason why I should have a wedding band other than wanting one, which I don't. My favorite line (directly quoted from you knotties) is "My marriage is still valid whether I have a wedding band or not".
Someone besides FI needs to reassure me that it's okay and not weird before I throat punch grandma or one of my friends.