The ages old quest to turn old computer fans into a desk fan finally yielded some results. Coroplastic was the mane evolution which allowed it. Other innovations were a stand capable of adjusting tilt. The mane advantage with this one was a junk microcontroller generating PWM for controlling the speed. There was absolutely no other use for this 40 pin PIC from 20 years ago. Most used fans don't have PWM support. The PWM runs at 25khz & goes from 0 to 100% duty cycle.
Grilles have to be ordered for any desk fan conversion. They're currently at least $10 for 4. You may also need a switch & pot, adding enough to the cost to make it more expensive than a purpose built desk fan. Only after many years of buying junk desk fans was there enough motivation & belief that old CPU fans could work better than purpose built desk fans to justify the higher cost.
For a given amount of noise & space, they do move more air than the Chinese versions. CPU fans could be stacked into a tower. With more noise, a smaller version putting out more airflow could be made. Jet engine amounts of airflow in the smallest space could be achieved with quad copter motors. That would best be fitted with CPU fan grilles.