The fact of their being ransomed is meant to provide an incentive to his readers to be OK with obeying the instruction of 1 Peter 1:17 to conduct yourselves
as sojourners, resident aliens, social misfits. After all, living as misfits is not appealing! But being ransomed
makes it worth it.
18 knowing that you were ransomed from the futile ways inherited from your forefathers, not with perishable things such as silver or gold,