I really think we aren't even thinking about the gameplay elements that could work with ray tracing. A legend of Zelda game where light can be manipulated in a more realistic way which provides various ways to solve the puzzle (think mirror shield puzzles). It would allow for those experiences to be less two dimensional. A first person horror game where the reflection on a window or mirror is the only way to see the patterns of an enemy so you can escape.
Besides looking pretty, I think this lighting solution has a lot of potential.







