The Magical Beasts Pets had brought big profits directly and indirectly, but it was easily forged by others. There were also the shortcomings of the pets being hard to rear and bring around.
Originally, when he was getting ready to domesticate, market and bring the Magical Beasts closer to the people, Yang Ling had already considered how to resolve these problems. Now that he had run into the issue of counterfeits, he might as well resolve all of these shortcomings once and for all.
Through the Imprisonment Restriction, he could seal a Magical Beast away in a crystal stone and make it into a Magic Hunting Card. So naturally, using the same method, he could make Pet Cards to seal away Magical Beasts Pets.
With a Pet Card that would recognize its owner with a drop of his or her blood, people could conveniently carry their Magical Beast Pets. They could keep it and summon it out whenever they want. It was convenient to use.