For neutral observers they are not comparable. But for the Israeli commander on ground, he has to decide how many troops he is willing to sacrifice if he enters ground war prematurely. Yes, Gaza is tiny, but Israel doesn't have the troop strength allies had during WW2. May be 1000 times smaller. Urban warfare can be more brutal than open field warfare. I still don't think they have a firm tactic to neutralize tunnels. That is why they are hesitating, aerial bombing with BLUs etc., How can they even fight when the enemy is somewhere 200 feet underground? This is all not-so-brave new world stuff.