...because it is so funny.

I don't know if anyone will agree with my interpretation that the following passage is a caricature of Marianne's 'sensibility'. JA seems to be making fun of her.
I am not sure if the words are a parody of Cowper's poem or some other poem.

"Dear, dear Norland!" [..]"when shall I cease to regret you? -- when learn to feel a home elsewhere? -- Oh happy house! could you know what I suffer in now viewing you from this spot, from whence perhaps I may view you no more! -- And you, ye well-known trees! -- but you will continue the same. -- No leaf will decay because we are removed, nor any branch become motionless although we can observe you no longer! -- No; you will continue the same; unconscious of the pleasure or the regret you occasion, and insensible of any change in those who walk under your shade! -- But who will remain to enjoy you?"

I find the whole very funny, but especially the highlighted parts.

Marianne had better take lessons together with Edward to improve her taste. To think that this is the same Marianne, who has been criticising him.
The sentiments are alright, but I find the stringing of words and sentences hilarious. Sorry Marianne.

She is definitely *trying* hard to be considered a person with taste and sensibility. I doubt that JA wants us to read this and think 'how well she expresses herself'.