Really? That's good to know. I did a bunch of Googling/research online and different sites I found seemed to say that each ticket within the multi-city ticket is considered a separate & independent flight, as if you had purchased two separate tickets. (I can't find it on the Emirates website itself, and the terms & conditions are too technical to understand!) I'd have only 4-5 hours in between arriving in SEA and picking up the next leg/ticket to STL, which is below my personal comfort threshold for separate tickets when arriving on an international flight. But you're saying if the DBX to SEA flight was delayed, I'd be protected on the SEA to STL flight even though it's a multi city ticket instead of a normal DBX to STL booking?
Thanks!