I just thought of an analogy for better understanding the uniquely Catholic reverence for the relics of saints.
Everyone knows someone, or has read about, who has lost a loved one in a tragedy, especially a child, and who as a result leaves their bedroom and things untouched. We know people who in their grief, especially parents, leave the very clothes the child last wore and held laying on the bed, in the closet, and all their things and furnishings as they were when they died. I know of fathers who still hug the clothes of their child who has passed, smelling the fragrance of their baby who grew up and left the world too soon in tragedy.
Catholics likewise have a love and attachment of comfort in their grief for the remains and furnishings of the saints. But with Catholics the aroma of comfort they "smell" is the fragrance of sanctity. Catholics venerate the remains of the saints because they love and long for what they cannot physically touch, because it is with God, but can "smell" because of the abundance of grace that was in that saint when he or she lived, and memories remain to give one strength. So just as the grieving parent is not worshipping their child's furnishings in an idolatrous way, but drawing sweet yet painful comfort from their clothes and room, so are Catholics not worshipping the relics of the saint, so much as they are pressing themselves against the containers that once held so much grace from God that it still resonates with that aroma of sanctity today, as they seek comfort from the hurts and uncertainties of life's hardships.
I hope this helps to better understand.
When a few years ago I kissed a relic of St. Francis I thought, "Old friend," with affection. I tapped my Franciscan rosary to the glass front of the reliquary with the same thoughts, so when I look at that rosary I think with fondness of him. I have it set aside in my "Catholic first aid kit," ha, not because I now think it is loaded with supernatural power, as it certainly does not work like that, but because if someone should ever need to "feel" the faith I can tell them that story and let them hold the rosary. The reason miracles do occur in connection with relics is entirely of God's will and is connected to the person's recognition of grace at work.