You can and will get mana fucked with reasonable regularity, there are insane combos that once executed you cant do shit about, there are trick decks that will annoy you and if you are in a rush to get your collection up, you can as always spend your rent money in short order
You can also deal with your life loss via cards in hand, graveyard, or in play
Raptor Hatchling: Oh yeah, this is the Enrage creature we need
It even shares the mana value of Gravedigger, so I get why this card costs this much, even if I would never build around it
You either hit your opponent for significant damage or you force them to lose creatures they may need
There are two cards with spellbooks in Alchemy: Tarkir that allow you to draft additional cards during play