As with most level 2 and 3 summoning spells, the number of white tigers you can summon with this spell probably isn't enough to really affect the battle. Don't cast this unless you're fairly desperate for some melee support and you don't have any better summoning spells available. Even a handful of White Tigers can actually be useful in the early game (i.e. grabbing resource structures away from wolves and faeries), and as a level 2 spell, it can actually be had that early.