Because it's not a -1 and gives you basically protection against 2 monsters/attacks.
Sure you can play some nice discard combos with Tribute to the Doomed and it could help you against an Ojama King, but I'd also prefer Man-Eater-Bug.
Can't wait to see some tilt decks with multiple Man-Eaters, Exploder Dragons, D.D. Warriors and Yomi Ships...
Any card that negate flip effect. Sasuke samurai, paladin of white dragon, baou spell card, etc. Or equip grarl spell card to any monster to lock it, but u cannot ever attack it unless u use any of the above mentioned card.