You make a lovely point Adrian. In Ch. 4 the narrator says “On the strength of Darcy's regard Bingley had the firmest reliance, and of his judgment the highest opinion” so it makes sense Darcy would want to set Bingley on a more discerning track which naturally is consistent with own point of view. I also see that Darcy would not believe a Mary Bennet with application but “neither genius nor taste; and …a pedantic air and conceited manner” comparable to his sister but (unless I missed it) we only have Miss Bingley’s description of the imminently estimable Miss Darcy who, not surprisingly, according to Caroline exhibits most of what is on her list of accomplishments:

"Oh! certainly," cried his faithful assistant, "no one can be really esteemed accomplished who does not greatly surpass what is usually met with. A woman must have a thorough knowledge of music, singing, drawing, dancing, and the modern languages, to deserve the word; and besides all this, she must possess a certain something in her air and manner of walking, the tone of her voice, her address and expressions, or the word will be but half deserved." (8)

Caroline’s descriptions of Miss Darcy:

"How I long to see her again! I never met with anybody who delighted me so much. Such a countenance, such manners! and so extremely accomplished for her age! Her performance on the pianoforte is exquisite." (8)

"Tell your sister I am delighted to hear of her improvement on the harp; and pray let her know that I am quite in raptures with her beautiful little design for a table, and I think it infinitely superior to Miss Grantley's." (10)

Accomplishments: "no one can be really esteemed accomplished who does not greatly surpass what is usually met with”
Miss Darcy: “How I long to see her again! I never met with anybody who delighted me so much”

Accomplishments: “A woman must have a thorough knowledge of music, singing, drawing”
Miss Darcy: “Her performance on the pianoforte is exquisite”
Miss Darcy: I am delighted to hear of her improvement on the harp
Miss Darcy: “I am quite in raptures with her beautiful little design for a table, and I think it infinitely superior to Miss Grantley's”

Accomplishments: she must possess a certain something in her air and manner of walking, the tone of her voice, her address and expressions
Miss Darcy: “Such a countenance, such manners! and so extremely accomplished for her age!”