Emulation apps in iOS 14.2 receive Just In Time (JIT) compilation, meaning they can run at full speed.
However, that doesn’t mean you’ll see emulation apps in the App Store, or even any other app using JIT. Testut told us that the current implementation works only for sideloaded apps, which are usually installed through Xcode and other developer tools instead of the App Store. In other words, this is a feature intended for developers with debugging purposes.
Check It Out: Emulation Apps Get JIT Compilation With iOS 14.2