Marketards
Designed by marketeers completely devoid from realism living in their own universe. A circular device is not easier to hold, nor likely more intuitive to work with. More likely, they managed to score a whole heap of cheapo circular displays left over from a test run from a manufacturer and never intend to deliver more than a single batch of devices (This is actually more common than you think. It is also the reason some kickstarters fail to deliver anything, because they find out they sold 200k devices, when they only have 20k pieces of a critical component, and buying 180k additional parts is prohibitively expensive)