When you're behind the counter, the questions come fast: "Which one lasts longer?" "Does this one taste good?" "Is this easy to use?" Raw numbers don't answer those. You need to know if the device performs the same from the first puff to the last, if it's simple enough for a first-timer, if the flavor is clear and not muddy, if the battery matches the way the customer vapes, and if you can actually keep it in stock. That's the framework that works.