even if the help offered was just aggrandizing herself, is not the same as telling Emma that her clothes are not fashionable IMO.

Mrs Elton has tried from the beginning to stand alongside Emma in many respects (taking JF under her wing, Hartfield's resemblance to Maple Grove etc), and to be superior to her (knowledge of the world) in others.

This here one monologue talking about gowns makes me think she speaks so because of how she sees Emma dress, and would have similar simple tastes.

CH:35
he took notice of my gown. How do you like it? Selina's choice -- handsome, I think, but I do not know whether it is not over-trimmed; I have the greatest dislike to the idea of being over-trimmed -- quite a horror of finery. I must put on a few ornaments now because it is expected of me. A bride, you know, must appear like a bride, but my natural taste is all for simplicity; a simple style of dress is so infinitely preferable to finery. But I am quite in the minority, I believe; few people seem to value simplicity of dress, -- shew and finery are every thing. I have some notion of putting such a trimming as this to my white and silver poplin. Do you think it will look well?"

Her self proclaimed knowledge of the world including parties and having aquaintances is where she feels most confident.
Her offering 'help' in introducing to people in Bath I put in this category.

It would be a *charming introduction* for you, who have lived so secluded a life; and I could immediately secure you some of the best society in the place. A line from me would bring you a little host of acquaintance;

She shows herself as having superior knowledge when they are talking about gardens of England.

"No, I fancy not," replied Mrs. Elton, with a most satisfied smile. "I never heard any county but Surrey called so."
Emma was silenced.

To Jane
"But you have not seen so much of the world as I have.

CH:34
Mrs. Bates, Mrs. Perry, Mrs. Goddard and others, were a good deal behind hand in *knowledge of the world,* but she would soon shew them how every thing ought to be arranged.

CH:33
I shall introduce her, of course, very particularly to my brother and sister when they come to us.