Right; this was my question. Technically, they are tubeless - just not in the original and traditional way the term was coined. I’m not using inserts, BTW - I went the whole-tire route, and - yeah - they’re solid.

I can’t really tell the difference, but I’m a casual rider. The benefit to me is that they’ve improved my riding experience immeasurably, as I no longer have anxiety about getting a flat on long rides. I hate changing tires in the middle of a ride; it’s dirty, and never easy, and takes time I’d rather be riding. So any extra firmness or weight which - again, I really can’t detect - is well worth being able to enjoy the ride without worry.

My wife, who still has tubes, says she can feel that they’re more firm, but not substantially. Mine are three years old now, and I think it’ll be interesting to see what improvements will be available by the time I ride the rubber off and need to change them. I’m really excited to see reviews about METL tires - also airless and tubeless, but not solid like Tannus.

In any case, I was mostly curious about the taxonomy. Airless, then, are not considered tubeless even though they don’t have tubes, merely because of how tire technology has evolved - right?