The suggestion is a good one, but especially for pillars, I just keep one un-upgraded one in my card stash, upgrade that one when needed, then go to manage deck, take out the card I wanted to upgrade and add the newly upgraded one from the stash. Seems about the same in time, only requires that I have a card in my stash matching the one I want to upgrade in my deck. But for pillars, this is a cost of 6 electrum, so it's almost nothing.
