Found this method on the internet.
To extract the arcade ROMs in this compilation, you need to do a memory dump while the game is running on a DS emulator.
I don't know the right method for MelonDS, but on DeSmuME, go to "Tools" -> "View Memory". On the memory viewer, select "Dump All" to get a 15MB bin file. Probably, you'll have to repeat the process for every game on the collection.