Dyson deliberately uses the spec of gallons per second instead of the more industry common cubic feet per minute (cfm) in order to obfuscate their terrible performance.
5.29 gallons per second is equivalent to 42 cubic feet per minute.
Now go compare that to some other tabletop fans, and you'll find that it's awful, positively a pittance.
And the air drawn in is the SAME as the air expelled. "Air multiplication" is a fraud. What actually happens is that the 42cfm is drawn in through a conventional blower in the base, that air is forced through a ridiculously narrow plenum (thereby resulting in a high noise level) and then through a narrow oval-shaped opening.
There is a legitimate aerodynamic phenomenon called "entrapment". So, yes, additional air is brought into the flow. But here's the difference vs. what Dyson wants you to infer from their marketing speak. There is NO increase in flow rate. What happens is that a relatively fast flow of air coming out of the narrow opening transforms into a wider and much slower flow of air. Energy is conserved. Momentum is conserved. So the effectively output flow rate, perceived by the movement of air on the fan output, is no greater than the input flow rate of 42 cfm.