How is third person used in "Interpreter of Maladies," and what is its effectiveness?

This short story is written from a third-person limited omniscient perspective, with the limited omniscient focus on the character of Mr. Kapasi. The narrator begins to tell us of Mr. Kapasi's thoughts and feelings very early in the text, and this continues as the tour guide begins to develop hopes that he might have some kind of long-distance relationship with Mrs. Das, as she reveals her terrible secret to him in the hopes that he can assuage her pain (or guilt), and as he realizes that the ideas he entertained about the pair of them will never come to be. This narrative point of view draws us closer to Mr. Kapasi, encouraging us to sympathize with and relate to him more than any other character; we are more apt to judge Mr. and Mrs. Das for their poor parenting and bad choices as a result of this perspective.

"Interpreter of Maladies" is a story in Jhumpa Lahiri's beautiful collection of short stories of the same title.  
It is undeniable that Mr. Kapasi is the central character of this narrative, seeing as he's the titular interpreter of maladies, and the third-person limited narrator gives us perspective into his thoughts and desires. However, if the narrative were in first person, written with Mr. Kapasi as the narrator, it probably wouldn't work as well as it does in third person. 
Lahiri has a very distinct writing style, which has a great combination of poetic description and straightforwardness. By using third person voice in "Interpreter of Maladies," we are able to get some descriptions and insights on Mr. Kapasi, the Das family, and their surroundings that are more varied and well-rounded than we would get if Mr. Kapasi were the narrator. For example, we probably wouldn't get anything like this line from Mr. Kapasi's mind: 

In the back seat Mrs. Das gazed out another window, at the sky, where nearly transparent clouds passed quickly in front of one another.

Or this one, a good example of Lahiri's use of poetic language and devices:

He found nothing noble in interpreting people’s maladies, assiduously translating the symptoms of so many swollen bones, countless cramps of bellies and bowels, spots on people’s palms that changed color, shape, or size.

It's also much easier to see the buildup of Mr. Kapasi's attraction to Mrs. Das from an intuitive third-person's eye than from the limited perspective of any one character in the story.