Mark probably included this incident in his Gospel because it illustrates how Jesus would open the spiritual eyes of His disciples that were still shut (cf. Mark 8:22-26). This is the last healing miracle that Mark recorded. [source][source][source]
"This second account of the blind being healed (see Mark 8:22-26 for the first account) concludes this central section of Mark ( Mark 8:27 to Mark 10:52) and serves as "bookends" of this section. Recorded as they were and where they were may be suggestive of the trouble the spiritually blind disciples were having in grasping the need for the death of Christ and the need for faithfulness in taking a stand for Christ in the midst of opposition. [source][source][source]
"This passage is the only place in Mark where someone called Jesus "Son of David." That Jesus accepted this title and healed the man is evidence that He affirmed the truth that He is indeed the Messiah." [1][source]