Jace, up to that point, was milling opponents to death, so we made sure he could do that
Youll play it in Blue control decks and spell matters decks, though
For example, if you attack with Incinerator of the Guilty and deal combat damage with it, use its triggered ability to deal damage, and then use Hard-Hitting Question to have it deal damage to another creature, it's still just one source even though it dealt damage three times during the turn
This usually occurs when a player desires a card that is cost-prohibitive, or is "playtesting" with many possible cards
Theyre almost certainly going to have some leftover cards in their deck that dont quite fit their new strategy, or their new strategy will be counting on exploiting some particular hole in the way their opponent sideboarded
Killing a creature is the goal but you can tack on a burn spell to kill something bigger or use it to make one of your attacks more favorable