splitting a digital signal

Yes, that was my plan. Use coax for both simultaneously. I've been led to believe that coax is better quality than optical, but maybe that's not the case?

Thank you all kindly for your responses! Based on feedback, I'm not inclined to try this. Even if it "kind" of works, just doesn't sound like an ideal way to go. I'm also guessing if it was something that worked well, I would have gotten the responses indicating so.
I naively thought, hey it's just ones and zeros traveling down that wire so even if split, they will still come out as ones and zeros!