Big tech firms are coming up with that aspect ratio to suit their clients since we are almost getting to a step where we won’t be using the 720 or 1080 but 4k henceforth.
If you get a good video shot in ultra HD and play it with a 720 resolution chances are that you might still get jaggies in your display but if it’s a compatible screen then it might be having the Anti-aliasing feature and you’re good to go.