What is the benefits of storing email and phone number in contact field rather then simply using phone and email itself only

Working with Data
1

I want to know the benefits of embedding the data like phone number and email in separate contact key like

Schema 1
{
   "name": "Shama",
   "contact": {
        "age": 18,
        "grade": "A",
        "school": "XYZ High School"
    }
},

Schema 2
{
   "name": "Shama",
   "age": 18,
   "grade": "A",
   "school": "XYZ High School"
},

What is the benefits of object schema 1 before schema 2?
I have seen this schema many place while someone learn the data modelling of mongodb.

However the querying of schema is still easy as compared to schema 1, then why schema 1 is so popular. Please anyone put some light on it.

data-model-denormalized.bakedsvg

Image Schema 1
{
   "_id": <ObjectId1>,
   "username": "123xyz",
   "phone": "1230456-7890",
   "email": "xyz@example.com",
   "level": 5,
   "group": "dev"
},

Is Image Schema 1 is better or not

2

From a personal point of view I find grouping data together makes a more readable document, you’re using the structure of the document to describe the data.
In our main application we have up to 1700 fields on a document that are all nested within groups that describe the type of data that they represent. This makes it easy to quickly navigate to the data that we want to look at, or to simply project out the areas of a document that we want to deal with as opposed to having to specify a project statement that has 100 or so fields in the definition.