Correct, Launchbox has no index of rom file types, or what file types a emulator needs, it will accept any file type you give it, so in cases like this, it would not now which file is the one the emulator actually needs. This is preferable to limiting file types for a arbitrary reason, and having to then maintain that list. Also Launchbox can be used to launch anything, not just games, so again, we accept any file types. Personally i converted my disc systems to CHD a long time ago, its one file per disc, and has very good compression, but also loads directly into a lot of emulators, no decompression needed.