A: To ensure stability. The emulator expects the code to be exactly as it was on the hardware. If the MCPX or BIOS file is modified or incomplete, the virtual hardware will not initialize correctly, leading to crashes.
The original Xbox had a notoriously difficult architecture to emulate, but the emulator has made massive strides in preserving the console's library. However, unlike emulators for Nintendo or PlayStation systems, xemu requires a specific set of system files to function. xemu files
extract-xiso -r game.iso game.xiso