Quick question about how Magic Lantern works

[film42]

I've read the FAQ and through a bit of the source, and it seems like Magic Lantern is pretty limited to memory manipulation.

My question is, is this manipulating the ROM's memory similar to Game Shark on N64? It seems like Magic Lantern is finding where the ROM stores certain settings, and you're then able to hack them to your needs (but still limited to features that exist in the ROM).

For example, Game Shark would give you unlimited ammunition by setting the value 99999 at 0xFF3321 (in memory where the game checks it).

I know this is a bit broad of a question, but I'm just trying to wrap my head around the process (it's very fascinating).