It's been more than 3 years since ray tracing features showed from developer sessions from WWDC. Today, they added more ray tracing features but I still wondering why there aren't any apps using the ray tracing while they keep adding more features? Is it because of the hardware limitation such as poor performance?
A ray tracing on iOS games or macOS software would be very interesting but I wonder why there aren't any of them available so far.
Path Tracer on the App Syore
I can't speculate as to why there are few apps using it. However, hardware support is indeed limited at this point and, until Xcode 13 released as a Beta today, the tooling was limited.
The raytracing API performs well today for many smaller effects, but at the very least, exposing the API now allows developers to implement effects and be ready to enable them as performance improves.