This could be true, but I have a friend who was sorted into Ravenclaw and trust me, as far as I know, she does not value being smart as much as having fun and being fashionable. Her friends and interests are absolutely more important than anything intellectual, and school disgusts her.
I was sorted into Hufflepuff myself, and I truly do value kindness over everything else, along with relating to Hufflepuff immensely.
I believe that the sorting hat is like an artificial intelligence with crystal ball abilities. We all know that Godric Gryffindor, Helga Hufflepuff, Rowena Ravenclaw, and Salazar Slytherin were incredible wizards and witches, and I believe that they possessed Gryffindor's hat (the sorting hat) with the capabilities to see to the innermost parts of the student's mind and soul, as well as into their future. The hat can see the student's values, actions, future doings, thoughts, desires, and yearnings, thus making an extremely educated guess as to which House the student would benefit from best.
Of course, I am not talking about the Pottermore quiz. I am talking about the legitimate Sorting Hat from the books.
The quiz is an educated guess because J.K. Rowling knows what each thing in Pottermore is exactly. She is the queen and creator of the Potterverse, and so since she created the digital quiz, she and her programmed answers, can make a very educated guess as to what House you should be in.
Although, I do think the digital quiz would benefit from an opinion question, like "Which House to do you think you belong in?" or "Which House's values do you value the most or value best?"
All in all, I truly believe and trust the choices the Pottermore Sorting Hat Quiz makes.
In the Bible, in John 7:24, it says: "Do not judge by appearances, but judge with right judgment."
It also says in James 4:12: "There is one Lawgiver, who is able to save and to destroy. Who are you to judge another?"
Although I believe the Pottermore test is just for fun, as is Harry Potter in general, I don't judge people on which Houses they get. I am not House-ist, as a friend of mine said. I don't care if you are Slytherin, Gryffindor, Hufflepuff, or Ravenclaw. Your House does not judge who you are! It just shows where you would be if Hogwarts was real, and it isn't, so no need to worry. :-)
Well that was fun to write!!