[CodeWriter23]

And still, the simulator is not the same as running on-device. Much of the iOS security model is non-existent in the simulator. If you’ve ever written an AppEx using a shared container, you know that. (Or you’re running to verify your code works on-device right now)

The simulator has to render the screen via the macOS display device, and I can tell you my trusty Radeon 5870 is only up for rendering about 5 frames per second in the simulator.

I’m pretty sure any Metal apps will be wildly different in the simulator.

I don’t even consider myself an expert iOS Programmer at this point, and I can come up with three examples off the top of my head. I’m sure there are plenty more. And there’s a reason every single iOS library or widget on GitHub requires all bug reports to be made only after testing on-device.