OK, just for future reference there is a FAQ here where some similar questions are answered: https://www.politepix.com/openears/support
The intention of the simulator driver is basically to let you debug everything else in your app in the simulator without Pocketsphinx breaking — that is pretty much the full extent of its ambitions :) .
The device driver is tuned for Pocketsphinx and the iOS audio unit so it will be fast and reliable under high load with a small memory footprint (and so it won’t decrease the lifetime of the device flash drive by reading/writing continuously when Pocketsphinx is running). It can’t be translated into a simulator driver that works identically with all the different desktop devices that it might host without that becoming its own project, and I’d rather put the time into the device code. I also suspect that if the simulator driver were really good, some developers might test on it and be really surprised by the real-world performance of their app.