Last season was full of mono red decks running Experimental Frenzy, an enchantment that allows you to play cards from the top of your library. But there is a significant drawback in it, which forbids you to play cards from your hand. Chandra, Fire Artisan solves this problem and allows you to do both on the same turn.
If you manage to protect it long enough, then it will also deal seven damage using her minus ability. But she also deals damage in case she gets attacked or damaged by non-creature spells.
Either way Chandra is a real powerhouse for aggressive red decks, and those have always been top-tier choices in Magic: The Gathering.