Most bikes are not silent. Worse, it's getting popular to make them loud. I was looking for an e-mtb recently. Tried a Trek ($4.5k down from $7.5k), ridiculously loud hub. Sales person claimed (falsely) that the more pro the hub the louder.
Talked to another dealer who gave me the same story.
MTB hubs are noisy as hell anyway, and yes, the more expensive the MTB the noisier the hub. For pedal bikes it's about being able to pedal without doing a full rotation and not losing power or wasting energy
It's kind of true. If you want the hub to engage right away when you pedal, you'll need the rachet mechanism to have more points of potential contact and those points will all make clicking sounds when you're coasting.
Talked to another dealer who gave me the same story.