I think putting the bills on a menu like Timers might remove some of the functionality that we currently have with them, like saving them to do the next day in addition to that day's bills plus the map locator.

I also don't think adding them to a menu working any better than viewing them out of key items based on how Custom Deliveries are viewed, which would be somewhat similar in nature. Using hotbars as Hasrat said (I already do this as well) is the better option in my opinion, though I know space is more limited for those using a controller set up.