There is definitely a need for the product. In fact, I just purchased on off Ebay for $235. I spearfish recreationally and the testing this product went through and the results is enough for me to spend that much for the peace of mind. I go in the water in Northwest Florida about 5 days a week. I go close to shore in generally 10-15 feet water depth. Lately, I've been spotting sharks anywhere from 1 to 4 of those 5 days per week. A few days ago having a 7 foot Bull Shark pass about 10-12 feet in front of me. I don't think there is "normally" concern about the sharks attacking but sharks are deadly creatures with small brains and are unpredictable. There are also a number of reasons they may attack mistaking identity of the target. I don't want to trust that the shark is not going to view me as a threat or mistake me for prey. The range of these devices is just a few meters, so, it would only effect a shark that was too close in my opinion. What I am doing in the water, spearfishing, is one of the worst things you can do around sharks to attract their attention. I don't mind spending the money to have the added peace of mind. The other spearfishers I've spoken with feel the same. However, the device is not complex and would not be difficult to duplicate. Therefore, I think the Manufacturer is simply asking for competition by pricing them as high as they are. A retail of half their current price would keep other companies from trying to market imitations. I haven't seen one yet but it's only a matter of time. The person that was almost bitten in half wearing one in Australia by a White Pointer was determined to be using it incorrectly. He didn't keep the device on the entire time in the water and was trying to move the electrodes too far apart for increased range. Instead it caused the field to dissipate.
I am sure they can't be 100% effective in every situation even if used correctly but if they just cut my chances in half of an attack, I'd be willing to spend the money.
I'm sure most reading this have seen the statistics and do's and don'ts of what puts you at risk in the water. There are just certain water activities that put you in the higher risk category and for those people I think they'll pay for the devices. Surfer's, Bodyboarders, etc. should really consider them too. A foot with a white bottom and tan top in the turbulent watter of a wave would look remarkebly like a mullet or some other fish. I think that's why you hear of surfer's feet getting bitten.
And about statistics....you have to take into account your situation and why you may be higher risk. For example, I saw a report that said you are more likely to be killed by a falling coconut than killed by a shark. Well, there are no coconut palms in this part of FL so that would drastically reduce my chances. I'd say if I see sharks 1-4 times a week in the water and I am in the water with them, and I'm swimming back to shore with a twitching bloody fish, my chances are greatly increased of needing a device like this.