Similarities between Walton and Frankenstein

I still wonder why Frankenstein decided to tell Walton his story. He stated that he wanted to share his experiences in hopes that they might serve as a warning for Walton, "You seek for knowledge and wisdom, as I once did; and I ardently hope that the gratification of your wishes may not be a serpent to sting you, as mine has been".  Why does he care for Walton in the first place? I think the answer to this question lies in the unmistakable similarities between the two men. Very early in Mary Shelley's Frankenstein we see that Walton has a close relationship with his sister. His tone and words of admiration in the letters he writes her make this very clear. When Frankenstein begins to tell his story, he also describes his more-than-sister in an affectionate and adoring manner. The two men are also both self-educated to some degree. They both took their education into their own hands to accomplish their dreams. Though Frankenstein attended a university, the science that led him to create life and his early fascination with learning in his youth were self inflicted. Walton received no former education, using the books in his Uncle's library to fuel his passion for exploration. These men share an obsession with reaching beyond the boundaries of science to benefit and make their own mark on humanity.