https://www.cnet.com/news/the-huawei-mate-x-made-me-a-foldable-phone-believer/

Foldable phones present a chance to shake up a coasting industry while also effectively doubling the amount of screen space you have to use on your phone. Because foldable phones are phone-tablet hybrids, they can command a higher price, which opens up an important revenue stream at the top end for companies looking to make a greater profit in a slowing market. 

But this new era of bendable screens also represents the Wild West of phone design: A phone could fold inward or outward, down the center or on two sides, or even bend back around your wrist like a watch. At this early stage, companies are working out what a foldable phone means. Right now, anything goes.