In the Seven Deadly Sins Olympics, Sir Walter would take a gold medal in vanity. (Distant runner-up: Vanity Smurf.) He’s so vain, he probably thinks this novel’s about him.
Vanity was the beginning and the end of Sir Walter Elliot's character; vanity of person and of situation. […] He considered the blessing of beauty as inferior only to the blessing of a baronetcy; and the Sir Walter Elliot, who united these gifts, was the constant object of his warmest respect and devotion. (1.6)
Sir Walter is vain about two things: his appearance and his title. The above passage, by referring to those two qualities as "blessings" and "gifts," points out one important aspect they have in common: both were given to him by his parents, rather than being rewards for his own hard work. Sir Walter was, in short, very lucky (making him oddly similar to the likewise "lucky" (4.4) Captain Wentworth, though their luck takes different forms). His self-respect, the above quotation makes clear, is not based on anything he’s accomplished in his life, but rather is something he was born into.
While being forced out of Kellynch could have been the blow that woke Sir Walter up to the possibility of making something of himself, instead he simply reshapes his vanity to fit the new setting of Bath. Anne is disappointed that her father’s vanity does not appear even dented by his reduction in situation.
She might not wonder, but she must sigh that her father should feel no degradation in his change, should see nothing to regret in the duties and dignity of the resident landholder, should find so much to be vain of in the littlenesses of a town[.] (15.5)
Sir Walter’s vanity is so well-anchored that even uprooting him from the grand surroundings of Kellynch Hall and depositing him in the smaller-scale luxury of a Bath townhouse doesn’t budge it. By contrasting "vain" with "littlenesses," the passage suggests another meaning of vanity: pointlessness. Sir Walter’s obsession with his rank could have meaning in the country where, as the "resident landholder," he has "duties and dignity" to give purpose to his position (for more on this, see the section on Kellynch Hall in "Symbols, Imagery, Allegory"). In Bath, however, where his only "duties" are to show off at the right places and make friends with the right people, his vanity seems (to Anne, at least) even more pointless than it did in the country.
In the end, however, Sir Walter’s vanity does Anne a solid in that it fuels his eventual acquiescence to her marriage to Wentworth.
When he saw more of Captain Wentworth, saw him repeatedly by daylight, and eyed him well, he was very much struck by his personal claims, and felt that his superiority of appearance might be not unfairly balanced against her superiority of rank; and all this, assisted by his well-sounding name, enabled Sir Walter at last to prepare his pen, with a very good grace, for the insertion of the marriage in the volume of honour. (24.2)
We might think Sir Walter approves of Wentworth for all the wrong reasons, but at least he does manage to see something to approve of in his new son-in-law. Is this the first step in the long-delayed education of Sir Walter? Or is he the same poster child for vanity he always was? Whichever way he may go in future, at the end of the novel Sir Walter’s still leaving poor old Vanity Smurf in the dust.