When I was young, my Atari ST's video out was a DIN-13 connector. They were as rare as hens' teeth, and my monitor was an analog RGB Magnavox 8CM515 with something else, so this sort of setup was literally what I had for about 4 years. Worked great, with the extra 'feature' that the whole display would twitch slightly to the side every time the floppy drive's track stepper motor would move on disc seeks :-)