https://squareup.com/legal/privacy
https://squareup.com/legal/seller-agreement
The Stand appears to be an entry in the niche of minimal POS (Point-of-Sale) setups, perhaps as an answer to an upgrade desire: "I like Square, but I need something more like a cash register."
It does seem to solve a security issue by tethering the iPad to the counter, which anyone whose phone has been stolen can readily appreciate.
I am surprised that the signature process is not done by tilting the device toward the customer and letting the screen display rotate. Perhaps Square is aiming more toward upscale retailers with great expanses of customer-facing counter space (who would also be more likely to pay the 2.75% transaction fee.) Perhaps the choice of white hardware is based on the same approach.
One thing though: while e-mailing myself receipts for business dinners is a nice-to-have feature, I am curious to know more about the privacy implications (probably wouldn't take but a moment to find out).