To activate the delirium ability on Scourge Wolf, apart from somehow getting a creature and land in the graveyard (which will likely be the hard part), you need to cast at least one instant and sorcery spell
Of course, Karmic Guide itself can be cheated into play through any number of reanimation spells or cost-reducing abilities, so this card is more often employed as a combo piece rather than as a straight-up five-mana Angel Spirit
Dont worry, Phantasmal Image is still a very good card to have around in your Minn and Sakashima of a Thousand Faces decks
Imagine a big Empty the Warrens making your spells cost a ridiculous amount less
That said, it's clear what this card is for - enabling land strategies that want specific cards on the battlefield but can't fetch them in more traditional ways, such as through actual fetchlands
For instance: A deck with a commander that costs two mana may avoid 2mv ramp because it anticipates playing its commander on turn two instead of ramping