Me neither. No restaurant can afford 2.75% per transaction going to Square versus the 1.64% which goes to Visa/Mastercard/Discover[1]. Fortunately for Starbucks, people are willing to pay much more for their cup of coffee than it costs them to make.
At the scale Starbucks will single-handedly bring them to, you really think they'll be using the default pricing?
Regardless, they're very clear on the post:
>Square will process Starbucks U.S. credit and debit card transactions, which will significantly expand Square’s scale and accelerate the benefits to businesses on the Square platform, especially small businesses, while reducing Starbucks payment processing costs;
Loss leaders can be a good idea sometimes, but when you're dealing with the sort of volume that Starbucks deals with, losing any money at all per transaction is a truly terrible idea.
You don't mention they also charge $0.27 per transaction. If you do the math that means that intuit and square both cost almost exactly the same for a $25 transaction (square is a little ahead because they also don't charge monthly fees).
So for transactions less than $25 square comes out ahead. I can think of plenty of restaurants that are primarily lunch driven for whom square would make sense (not to mention coffee shops).
Comparing Square to traditional Intuit isn't apples-to-apples. Intuit's GoPayment is a direct Square competitor and has roughly similar pricing: http://gopayment.com/pricing/
Fortunately for Starbucks, people are willing to pay much more for their cup of coffee than it costs them to make.
One interesting problem with this deal is that it will call attention to just how much money Square users really are spending at Starbucks.
Imagine if most or all of the charges on your Visa bill were from Starbucks, such that you couldn't help but see the total staring you in the face every month. That's the position a Square user will find himself/herself in, at least until more merchants come on board.
[1] http://payments.intuit.com/pricing/