Why did Bimbi (ch. 10) make such an impression upon Malcolm? 

I believe that Bimbi made such impression upon Malcolm because he has never met anyone like Bimbi. As in Bimbi never cursed or yelled but he still got everyone's attention when he talked. H e had power in his voice and his opinion mattered. This was new to Malcolm because was used to talking in slang and didn't care about education much. When he heard and saw Bimbi talking it was a new fascinating experience for him. He was drawn to the respect and tone Bimbi used while talking. Bimbi was educated and mannered which was way different from Malcolm's world.