Agree. I think we have several factors at work here. First, some want a "taste" before commiting to a big set up. I get it. Others might have the space / budget limitation (or just love the look of a small water world). In a recent live stream I got into this exact subject. Big systems are far more forgiving. Stick a hand that was recently treated with a powerful antibiotic soap into a 150 gallon and it barely registers. The PPMs dilute to nearly nothing. Do the same thing in that 5 gal nano and it's game over, and if it's the person's first tank, it might be the end of their fish keeping. Bigger is better.