I like marking off my cards (sleeved, of course) since it's easy to track things like conditions and soulstones when it's easily erasable on the card. Otherwise you end up with a fistful of dice next to a Rail Golem because it's taken a few wounds, it's got Burning, an enemy's put Blight and/or Slow on it, for instance...
I like being able to just write stuff on the cards, personally.