The auto mill ensures one does not have a stash of cards to mill and get a ton of meteorite powder when they change the economy. It is not an accident that it has been implemented, it is a maneuver to strengthen the pillars of their new economy (or to prevent us from sabotaging it, however you see fit to interpret it).what the developers are basically saying is don't play our game for a month or you will get screwed
Sure one can use ore and buy 400+ packs and gather stash but they cannot do anything regarding one's gold without causing a massive riot and getting rid of the extra cards is better than doing nothing.
We have to wait and see what the changes will be, bearing in mind that they probably feel the need to make MP scarcer if they want to sell it. If we all can have a good premium collection just by playing, how in hell are they going to earn money from the game?