If you take the notion of a magical world seriously (and that's why we're here, isn't it?) blink dogs make sense—on a globe bathed in eldritch emanations, magical flora and fauna are bound to appear. Traditionally, blink dogs have also been enemies of TSR/ Wizards of the Coast’s displacer beasts, but Paizo's substitution of phase spiders works just as well (and explains why phase spiders haven't decimated the Material Plane by now). Add to that the canines' fondness for astrology, and you have lots of reasons a pack might aid—or attack—your PCs.
A bronze dragon astronomer and a blink dog pack argue over the import of a comet in the southern sky. Somehow the comet's passing is linked to an ostinato of necromantic pulses and the coming of strangers—a party of sellswords—to their lands. The bronze dragon urges caution, but the blink dogs are determined to harry the party and test their reactions. As lawful good creatures, they will not kill without reason, but they will savage any spellcaster who shows the slightest propensity toward using the vile magic.
When adventurers finds themselves beset by phase spiders, a blink dog sage comes to the rescue. A sorcerer of the destined bloodline, the sage reveals his destiny has arrived. He has been meant to find the party and recruit them against an evil from the void between the stars.
Planewalking heroes are asked to broker a peace between the phase spiders and the xills (having fought both, they are considered ideal impartial interlocutors). If they reject the offer, they will be attacked by champions of both races. if they accept, they will be hounded by blink sages instead. If the two Ethereal enemies ever stop fighting, the blink dog alphas believe, the Material world is doomed.
—Pathfinder Bestiary 2 47
All of the above comments apply even if your world is not a globe. Substitute disc, ring, plane, conic section, asteroid shard, Möbius strip, or what have you.
Also, I'm guessing blink dogs hate kamadans, too.