God hears them. Every word, every sigh, every tear. Christ also hears. That is pictured here in Revelation 8. The angel of prayer is given incense.
Incense is an ancient substance used to symbolize prayers.
Those extra prayers are the holy prayers of the Saviour. His intercession mingled with our prayers and going to the Father. Great heavenly glory. Prayers coming from earth. Prayers coming from the Saviour.