It doesn't prevent activated abilities from cards in any zone other than the battlefield
Buffs like this, with double strike, are all you need
You're locked in a Standard green midrange mirror, with you playing white-black-green and them playing something that at least looks pretty similar
If the target of Furnace Skullbomb's last ability isn't a legal target as the ability tries to resolve (probably because it has left the battlefield), you won't draw a card
Cards like Skrelvs Hive, Mirrex, Reject Imperfection, and Bring the End would all enhance the power of this card as a control finisher and sweeper in competitive play
Depending on which you choose, the price might change by a lot