Often we think of prayer as valuable, or enjoyable or even beneficial. It is powerful. St. Thomas Aquinas explains that certain graces are given if we pray. God wills to give certain graces in reponse to prayer, our own or that of someone else's. A holy Dominican, Mother Mary of St. Peter, said that God has arranged things this way, that prayer is often a condition for receiving graces.
Prayer is real.
It is causal. C.S. Lewis stated that the reason God arranged things this way is a great honor to us. To give us the dignity of being causes. Our prayers really count, They have an effect. Our prayers do help.