The images projected by Kirlia are not simply the product of their imaginations, but pictures of a vast multiverse which they and only a few far more powerful psychics and legends can see. To these people, Kirlia are the world's best window into the unknown.
Although science is at times skeptical of the discoveries claimed by some Kirlia, for these pokemon are also capable of illusion, their dimensional sight has made an enormous impact on the popular understanding of the many worlds beyond our own. From the bizarre architecture and floating platforms of the Distortion World, to the abominations of Glitch City, to the pristine White Forest of ancient times which shall someday be built into the hyper-industrial Black City of the future, Kirlia have entertained many with the fascinating and beautiful dreams of worlds far beyond our own comprehension. Giratina is often credited with controlling dimensions as Dialga does time, but if it does, it has given this strange psychic pokemon some portion of its power. Kirlia are used for religious purposes in Sinnoh among Giratina's followers, but this can not compare to their use for exploration, for religion is merely one facet of Man's desire to understand the unknown.
What ordinary Kirlia can not do is offer a pathway to these worlds, although certainly many have tried. The strain of opening the dimensional gate and not simply projecting the other side is theoretically manageable, but only a few powerful yet poorly-documented Kirlia have ever claimed to manage it. Yet great trainers still flock to these pokemon, give them Everstones, and strive to make them as strong as possible, for once you have conquered this world, what is there to do but explore another?