The use of tablets as a POS terminal is a growing trend in the retail sector. A study from U.K. research firm Timetric found that between 2011 and 2012, the number of "mobile point-of-sale" terminals registered by businesses worldwide more than doubled. While researchers do not see that level of adoption to continue year-over-year, they do project that the percentage of systems like Square, Intuit, PayPal and others, will jump from fewer than one-fifth last year to nearly half by 2017.

According to a recent Wired article, using an iPad as the company cash register is about to move from a novelty to the norm. Marcus Wohlsen, the author of the piece, framed the article around a trip to a local coffee house where he he paid, tipped and declined a receipt when the employee behind the counter handed him an iPad during the transaction.

"In that moment, I had just paid for coffee on the same kind of device I use at home to watch Mad Men, page through pictures of my kid, read The New York Times and video-chat with my dad. Can your cash register do that? Daily life really didn't used to be this way," Wohlsen wrote.

He added that in a few years, the interesting part to that story will not be the use of a tablet during check up but rather what kind of coffee was ordered.

It seems clear that the functionality and benefits that come along with using mobile devices as a cash register will continue to rise in retail. Merchants need to get onboard this trend to make sure their businesses stay ahead of the competition.