I thought this deserved another post, talking on another forum about this and had someone explain it a bit more eloquently :
"Emulating a cart" doesn't make any sense, really. There is no difference between an Everdrive and an actual cart, technically speaking. Underneath that cart, the same ROM is there, waiting to be loaded and played. Using an Everdrive just means you have a cart that can load any ROM you want, and each ROM is assumedly ripped straight from an original cartridge. There is exactly zero difference.
Emulating the actual hardware is a HUGE difference. Emulators are built by reverse-engineering the console itself, through all manner of hacky shit. Honestly don't know how people do it entirely, but I assume it's probably by analyzing ROMs and seeing what system calls are made and what the expected behavior is, along with knowledge of the hardware itself.
The caveat is that these emulators wind up being inaccurate in several ways, whether it be framerate, sound, resolution, etc. Whatever it is. Emulator accuracy is a huge deal to a lot of people, and the best way to avoid having to deal with an Emulator is just to play on the original hardware to begin with.
Someone else also chimed in:
Emulation typically means you're attempting to mimic or recreate how the original hardware handled specific code (the game). The game is the same, whether it's on an SD card, flash cart, USB drive, etc. The important part is how that code is interpreted. Emulator typically involve a combination of reverse engineering, documentation, guesswork, and general programming skill. Not to mention that the emulator can produce wildly different results based on the hardware and OS it's running on. The game code is always the same, and is never technically emulated.
