The Switch is a little more involved, simply because it requires firmware and encryption keys from a switch. Sort of like the BIOS files that PSX emulators need, these files tell the emulator how to actually decrypt the game. Because Switch games are encrypted, so they can’t be played without extracting keys that are stored on a real Switch. There’s also the issue of game updates, DLC installation, etc… So it’s not as simple as just “download the ROM” anymore.

Sure, you’re 90% of the way there. But that’s not super helpful when everyone knows (and expects) that 90%. It’s the last 10% that trips up newcomers, and it’s what causes the most questions, (just like OP’s.)