Square is a very exciting product without a doubt. And it's also the type of product that might bring harm to the economy or society. The very common practice

Square is a very exciting product without a doubt. And it's also the type of product that might bring harm to the economy or society. The very common practice of paying "cash in hand" to certain professionals such as plumber, house cleaner and many others, can take up a whole new level. Resulting in very costly loss - quite possibly - of billions of dollars (depending on the country) in tax evasion. Of course not all freelance and self employed professionals dodge their taxes but would be silly to say a lot of them don't. Also, if it fall into the wrong hands, it can be used by pickpockets and other crooks, to skim the victim's card minutes after the card was stolen. One might argue that credit card transactions are not settle in minutes, but rather in days and sometimes only after 30 days that the payment was made, the merchant/crook would be credited with the monies. But some transactions do credit the merchants within few hours or a day or two - and for those type of transactions crooks could setup their biz and start transferring monies to several accounts making the funds very hard to trace and of course, getting a new device every so often because it wont take long until Square's fraud prevention realise that one particular device is the root of too many complains/fraud alerts