The answer may be found in the truth that the Psalms are always prayed on behalf of the whole Church, indeed the whole world. One may not oneself find the opening phrase of Psalm 130 particularly relevant to one's spiritual outlook at the moment, but someone in the circle of family, friends, and fellow parishioners may.
Or, if a pastor knows of a person in his parish who is depressed and whose life is full of trouble, he can pray the Psalm on that person's behalf, putting the words of the Psalm, on that person's lips, so to speak.
Or, one can pray on behalf of the whole Church in time of crisis – and especially the suffering Church in places where war and oppression hold sway. For a moment, the one praying the opening phrase of Psalm 130 becomes the whole Church.
One can also pray the first words of Psalm 130 for that part of humanity which experiences the broad range of joy, elation, peace, on the one hand, and tragedy, sadness, and psychological oppression, on the other.
Hebrew poets composed the Psalms. Accordingly, the Jewish people have a special claim on the Psalms – notably Jews for whom the horror of the Holocaust is seared into their hearts and souls to this very day. Many Jewish people lost their faith because of the Holocaust and feel that God abandoned them – if there is a God. Praying the Psalms on behalf of downcast Jews is a good and worthy act.
One can also put the words of the Psalms on the lips of the faithful Christians and Muslims of the Middle East who are suffering terribly, with seemingly no let-up. They may not be able to pray, but we can pray of their behalf.