Foldable dual screen phones seem like a solution in search of a problem. Samsung patents reveal what the company engineers believe might be the right problems to solve for a successful foldable phone.
As we saw before, providing gaming controls on the second screen while gameplay runs on the other screen is the most obvious solution its the Nintendo 3DS, but reborn as an Android phone.
The patents also talk about using a stylus the S Pen presumably. Graphics artists often draw on a stylus-enabled tablet that is not a screen having a separate screen means you dont cover up the artwork with your hand or stylus. This is especially important when you have a small surface to work with (like, say, on a phone).
Each half of the phone also has its own camera and speaker, which may enable other uses. The rumor mill has been telling stories about the Galaxy X phone and despite leaks and patents, there is still no official word on when the phone may launch.
Source (in Dutch)