In short, the Gold version of PPSSPP for iOS is stuck in review, and I am thus unable to update it at all, and I am also unable to update any aspect of the store presence, like the description. For now, I recommend all iOS users to use the free version of PPSSPP, even if you paid for Gold.
PPSSPP is an open source PSP emulator, that lets you run your own PlayStation Portable games on your various devices. PPSSPP is officially available on Android through Google Play, PC, Mac, and recently iOS through the App Store. There is also a Linux flatpak build. The project is ongoing for more than 11 years now, and has been downloaded over 100M times. It has millions of active users on Android.
PPSSPP is completely free to download (and compile if you want, since it's open source) but there's also an optional paid version to finance the development and maintenance of the project, buildbot, website, etc.
The paid "Gold" version is, except cosmetically, identical to the free version. I've chosen this monetization model on the App Store to keep it consistent with the other platforms, where it's often the most practical one.