you wont be able to read the dreamcast disc, as it is a proprietary GD-ROM format. you would need to use your dreamcast to read the game disc, and transfer the image to your computer in the form of an ISO or something similar. or you could always cheat the system and try to find a download of the game
If you're spending that kind of money, you might as well spring for an HKT-01 dev kit too, so you can write your own games. But yes, that possibility is quite real. If you really want to play original GDR's in the emu, then that is a route that you can take.