These sell because of the emphasis on performance rather than filterarion, a common misconception.
Kids pop in these filters, notice the louder sound and slightly better air flow, and think that this is it.
What they don't realize is the compromise on filtration.
Like Xulfiqar showed, if filters have such big holes, air flow has got to be better than stock but at the cost of a myriad of bad things going into the engine.
I for one would never want to wear out my engine just for some fancy sound and a minute difference in acceleration.
On a personal level, I found that replacing OEM every other week cost me the same as a fancy filter every two months.
I do the former now, and don't notice hampered air flow anymore. Ever.
Sent from my GT-I9300