If you do, you do so as part of the resolution of that ability
There are few cards that have not just single decks, but multiple archetypes named after them
Ice Age tend to be goofy as well
General Leo Cristophe* If Leo cost a bit less mana hed be much higher up on this list, as at 5 mana returning one cheap creature, and growing based on how many creatures you have is just not that good especially given he lacks any protection or evasion
Its also an instant that can fire off when your opponents shields are down and can be foretold to save a bit of mana, increase the surprise factor, and net a whole mess of life
Everything that Bloodthirsty Adversary does is good, but everything that Intrepid Adversary does is exactly what white aggressive decks would be doing at that stage of the game anyway