The reason to play this deck over, say, TPS, is because it is simply faster and more broken. Pure speed gives it an undeniable advantage. The real question is does greater speed and brokeness make up for the lack of fow and a stable mana base?
It's faster, no doubt about that, but more broken??
It depends a lot on the defenition of "Broken". Due to extra acceleration it might pump out bombs earlier on, but I wouldn't call the deck more "broken", since it can't consistantly produce winning hands that might make it more broken than TPS. They basicly play alot of the same restricted cards, Mean-Death-Long (

) just has more explosive mana producers and less land.
You have more change at a more explosive hand, but you also gamble much more, and if your opponent is able to stop your first threats you might still be able to draw into enough bombs to overwhelm your opponents but this leaves your mana-base totally open to all kinds of disruption, and with many decks focussed on mana-denial I just don't think the time is right for this deck.
This might also be because of my local metagame, I don't get too beat up scrubs with first-turn kills all the time, but I have to fight for every match so I feel much more confident with a Deck (and mainly a manabase) I know I can rely on.
Edit: Sbed xantids give it a big boost in control matchups vs TPS which basically must rely on it's original protection cards in this matchup.
With soo many deck focussed on mana-denial Swarm doesn't seem to be the bomb it once was. You are always spending a turn casting it, and that turn might just be the turn in which your opponent Wastes your land and drop a chalice for 0.
Few decks are really able to control a deck that keeps topdecking bombs just by countering them, they mostly have to rely on disruption to make sure you can't overwhelm them.
Koen