You’re basically trading energy to move higher volume of air. The fan can move smaller amount of air at higher speed, but larger amount at a gentle breeze feels nicer and helps with circulating the air in the room better.
You could achieve it by taking that exact motor and slapping a bigger fan onto it, but that looks less cool and probably produces more noise? Maybe there’s some efficiency differences if the motor is better at spinning fast, but as a spherical cow in vacuum it should be similar.
Yeah, the fan being completely shrouded in plastic will dampen a lot of noise. And for the price, the fan is probably well balanced and somewhat optimised. From what I recall, the dyson bladeless fans are near silent.