Sagas have a different template where they enter the battlefield with a lore counter and then gain an additional counter each turn
For example, if one World at War creates a second combat phase and a third main phase in a turn, then a second World at War is cast during that third main phase, no additional phases are created
An extra draw at the end of your turn plus some tokens or recursion respectively can add up to some serious value
Take the Promising Stairs, and while the other side helps you tutor for rooms, the right side can win you the game with just four split cards
This ability essentially works as a wizard tutor while being on cards that can serve other circumstantial purposes
Dont get me wrong, Miles will still be quite strong, but the back half is a beater, especially if you transform it after you already put a +1/+1 counter on it with Miles