I was able to do transfer my Pokemon Ruby save from my retail cart, decrypt and use with a ROM.
Depends if your game has tools out there to help you. If it wasn't for project-pokemon I probably wouldn't have my save extracted. I did use Powersaves for the process though, you'd need something to backup the save, as Gateway doesn't work for 7.x encryption.
Pokemons are Card2. Kingdom Hearts is Card1. They're different.
Save Dongle and GW Launcher are different, too.
So don't try to use your own experience to represent his.
For details, what Save Dongle dumps is a header-locked .BIN file without any conversion and extraction.
Powersaves dumps saves in SaveDataFiler format which is fully extracted.
GW Launcher dumps header-locked .SAV file.
MT Launcher dumps .SAV file too. If the game has old encryption (KeyY 2.2), MT Launcher auto-converts the dumped .SAV file into a header-free one. If the game has new encryption (KeyY 6.0), MT Launcher dumps a header-locked one.