Why don't Premier matches affect map-specific ranks?

You can win 1000 Premier matches, and you still won't have any map ranks unless you explicitly queue for "normal" matchmaking on a specific map instead. 10 wins required per each map nonetheless, too.

There's no practical difference between the two game modes besides the veto at the start, so why not just have Premier Elo go up/down on a win/loss like normal, but also have the Premier matches' results affect your map-specific rank(s) as well? You could then even see how your performance is spread across maps since you'd likely be higher rated on some and lower on others.

Would be a way better system imo.