Do you have ears and fail to hear?
The story of the blind beggar who yells out: "Jesus, son of David, have mercy on me!" isn't about the literal blindness of Bartimaeus. The story is really about the blind people in Jesus' inner circle. His closest disciples who could not see what he kept trying to show them were the truly blind that day. Bartimaeus, on the other hand, saw clearly who Jesus was and how to respond to him: with pure faith.