From the catechism-
2559 “Prayer is the raising of one’s mind and heart to God or the requesting of good things from God.” 2 But when we pray, do we speak from the height of our pride and will, or “out of the depths” of a humble and contrite heart? 3 He who humbles himself will be exalted; 4 humility is the foundation of prayer. Only when we humbly acknowledge that “we do not know how to pray as we ought,” 5 are we ready to receive freely the gift of prayer. “Man is a beggar before God.” 6
2562 Where does prayer come from? Whether prayer is expressed in words or gestures, it is the whole man who prays. But in naming the source of prayer, Scripture speaks sometimes of the soul or the spirit, but most often of the heart (more than a thousand times). According to Scripture, it is the heart that prays. If our heart is far from God, the words of prayer are in vain
2111 Superstition is the deviation of religious feeling and of the practices this feeling imposes. It can even affect the worship we offer the true God, e.g., when one attributes an importance in some way magical to certain practices otherwise lawful or necessary. To attribute the efficacy of prayers or of sacramental signs to their external performance, apart from the interior dispositions that they demand, is to fall into superstition.
I can’t speak for the saints, or any other person. However, because of the ritualistic aspects of the rosary one can become focused on the execution of the rosary vice the core aspects of prayer. Raising one’s heart and mind to God, bringing our heart closer to God. The Rosary is one means of doing that, but not the only way, and I think occasionally reminding oneself of the goal vice the method is helpful.
Some folks don’t find the Rosary as useful as other methods of prayer.