Do you know why to use Entity Framework?

Entity Framework allows you to provide a strongly typed object framework (ORM) over your database. This helps abstract the database away allowing it to be replaced with other technologies as needed.

using (SqlConnection conn = new SqlConnection())
{
    conn.ConnectionString = "Data Source=(local);Initial Catalog=Northwind;Integrated Security=True";
    conn.Open();

    SqlCommand cmd = conn.CreateCommand();
    cmd.CommandText = "SELECT * FROM Customers WHERE CompanyName LIKE '" + companyNameTextbox.Text + "%'";

    bindingSource1.DataSource = cmd.ExecuteReader();
}

var results = dbContext.Customers
    .Where(c => c.CompanyName.StartsWith(companyNameTextbox.Text));
customersBindingSource.DataSource = results;

// Or even
var results = dbContext.Customers
    .Where(c => c.CompanyName.StartsWith(companyNameTextbox.Text))
    .Select(c => new
    {
        c.CompanyName,
        c.Phone
    });
customersBindingSource.DataSource = results;

1. Making queries that are independent from specific Database engine
2. Strongly typed fields - SQL tables/entities have intellisense
3. More readable and less code
4. It's easy to chain more operation like OrderBy, GroupBy, FirstOrDefault, Count, Any and many more
5. Developers are generally poor at writing SQL, so using code constructs makes writing queries much easier