He's Bald and wins a place in society ?
Sir Walter's remarks on Admiral Bald-win shows both his obssession with appearance and his petty tendency to mock people by their looks.
I think JA deliberately used the name of Lord St. Ives 'whose father we all know to have been a country curate without bread to eat' (ch.3) to show Sir Walter resents the social mobilty of professional navymen.
According to footnotes by G. Beer in my Persuasion ( Penguin Classics. 2003) Lord St. Ives, like Nelson, was the son of a country cleryman. (shades of Wentworth's brother over at Monkford ?)