Ugh. Lack of good ghosts to run off (IMO!!!). See the difference is that there's a CHEAPER way of doing what he's doing. You don't need to have monsters die to gain CA with others whereas with this guy you HAVE to kill your own monsters to gain CA.
See, Piercer and Horrid Wurm both run off tempo whereas our ghostly friend runs off passivity and is more control oriented. Not that a control-base is bad, but generally in Duel Masters (And YGO), passivity tends to lose out to aggro, tempo-based decks.
*note: I do understand where you're coming from. And I know that you can usually gain more CA with this guy in the long run (you need to bring back 2 before it's CA tho, whereas a single attack from piercer or wurm is already CA). So yeah, it's good in its own way, but I'd prefer the tempo.